# Firearms and Shooting > Reloading and Ballistics >  Wilcats and Pressure

## Spanners

I want to make the point in starting this thread that its intention is to not turn into a brawl or a dick waving comp as to whos right and wrong, but to discuss a topic that comes up on occasion with 'he said, she saids' more than actual facts

SAAMI pressures are set from loads submitted to them for approval as to ascertain standards for safety, interchangeability, reliability and quality.

The issue comes when new wildcat calibers are formed, either on new cases and less so on existing designs that have been necked down or up etc
What is the max pressure?

You can use DIY or 'laboratory' gear like strain gauges to obtain a number -we've had the discussion of the downfalls of the units before - and I will draw note to the fact that the Oehler that 'some' hold as the be all and end all - isnt even made anymore - also given the fact there is no way to calibrate the unit and also inputting the correct data as to tensile strength of the material as to get a accurate hoop strain leaves room for many errors (bead blasting a barrel will change the SURFACE hardness but not the true tensile of the material) the whole system leaves alot to be desired.

We are then drawn to the fact that 2 very similar guns, Mr A can get XXX out of it, and Mr B cant
Mr A keeps his mouth shut as to what, how etc he is doing to get XXX, but B will state the pressure is too high based on his results, which is entirely fine.
Mr B has hit the limit with his combo, but Mr A still has room to move for more powder if needed.
Thus a pressure of 'Max ZZZ' is quoted - yes maybe for Mr B, but given that there is NO SAAMI pressure, these are custom cases, in great big thick actions etc, is THAT the pressure, and how do you quantify it given the fact the Mr A is 'maybe' higher, or 'maybe' lower and just doing something different that everyone else hasnt picked up on.
Where do you call it quits and Max? when primers puke, brass is trashed, bolt has to be hammered open, or you pick a number like 87654 psi?

I spent a few hours the other week, measuring, cutting open cases, firing etc a caliber/load that is said to be 'way over pressure' by someone else shooting it.
5 firings on a cases that hadnt been full length sized EVER, and would still chamber, brass that had no measurable differences from virgin other than 2 1/10s of a thou as to be expected (I can drive a mic) no extractor or ejector signs, perfect primers - without pressure gear, if you were loading any run of the mill case - you would say was PERFECT.
The shooting of this caliber at range, using 2 different ballistic programs show the projectile was actually a little faster and or better in BC than already expected

If I build an action out of 4" round a run a custom case with meat in all the right places; which has no SAAMI data, and achieve results that dont hurt the brass, primers etc and the gear says (to make it simple) 100,000psi for eg, is that too high, or is that now an acceptable pressure for this new caliber?
The action isnt ever going to fail and the brass is  built like a tank - so where do we stand now?

When you;re pioneering something new, who is right, the guy at the front of the pack with the best results/performance or the guy that hits a brick wall?
Maybe those at the front of the pack have a few tricks up their sleeve? I know that I learnt a few in the time I played around for my own interest - things that I would have _never_ have considered, thought of or expected, but were proven in black in white behind the butt.

I came across something very similar recently online on another caliber I have interest in (big bricks out of an AR). Astronomical performance, and those that cant get there.

Soooo... you invent some new fangdangle case - whats the limit??

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## tui_man2

Is it me or reading that you just want a arguement??

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## gimp

If you're getting a speed you're happy with, and not piercing/flattening primers or have "sticky" bolt lift, destroying cases, stretching primer pockets etc, then that's enough

Who cares what the "actual" pressure is at that level? There's no downside to it if none of those things are happening





> Soooo... you invent some new fangdangle case - whats the limit??


So for me, the limit (on anything, not wildcats 'cos fuck them) is where shit that is inconvenient to me starts happening, ie, the above things.


Different in a semi-auto or lever action - I'll just stick with book max to be sure.

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## Spanners

Read the 1st paragraph and the last 2 lines

I have a genuine interest in all things guns and especially old ball stuff and the point is with odd ball stuff what is right and wrong, how and why is this conclusion come to?

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## Tui4Me

I'd be more concerned about bolt locking lugs under excessive pressure and possible damage to the bolt or action from lug set back.

Plenty of articles floating around on the subject by reputable people.

no point spending big $$$ on custom actions and action blue printing if after 100 shots the bolt lugs are not engaging evenly.

Note that I'm not saying that this is likely to happen to any particular rifle or load discussed on this forum.

Simply saying in response to your post above that it's well documented and as bolt lugs are typicaly harder than an action, it's an easy way to kill an expensive new rifle. (if you believe the experts  :Thumbsup: )

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## Spanners

On standard action yes - but what about a big fuck off custom action ?

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## Tui4Me

I'd pick that the bigger harder lugs will make bigger fuck off marks?

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## L.R

Yes I'd say 100k pressure is very safe in a big fuck off Barnard PChey action.

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## gimp

If you've got high enough pressure to do that, surely your brass is going to be showing signs first

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## Spanners

100k was just a number that was even and plucked out of the air. orgianlly had 200k but is fantasy numbers. NOT saying anyone is shooting it but who/how do we/they/anyone ascertain what is safe or acceptable in an action and case combo that there is no standard for?
What if I soak projectiles in goat piss for a week and it makes them shoot 100fps faster than anyone else due to some chemical reaction - thus bar is raised. 
Is it now unsafe because the speed I get is faster than the norm?
The bar is now raised as I have a secret sauce ....

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## Tui4Me

> If you've got high enough pressure to do that, surely your brass is going to be showing signs first


You would think so but according to the articles apparently not.

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## gimp

well there you go


just another great reason not to bother with wildcats!

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## Spanners

Simple mechanics says low tensile will fail before higher.

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## gimp

which = brass


What if the brass is held by the action so it can't fail


stronger action, less elastic deformation, brass can take more pressure??? I don't know anything about this.

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## Tui4Me

Pressures, Case Strength and Back Thrust

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## Tui4Me

http://www.longrangehunting.com/foru...re-safe-40117/

This post by Kirby Allen is what I was after. Very interesting reading and relevant to spanners post regarding brass failing first.

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## The Claw

> Rem 700 action how much chamber pressure is safe? - LongRangeHunting Online Magazine
> 
> This post by Kirby Allen is what I was after. Very interesting reading and relevant to spanners post regarding brass failing first.


Thats good enough reason for me to want to question the pressure being run to achieve XXXX velocity... And I know that every barrel will be slightly different etc, but surely not to the point that the differences reported in other threads would be explainable.

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## Tui4Me

Notice in the 1st article I posted there are some very interesting points regarding ackley case shoulder angle, suggesting almost straight taperd angled cases reduced bolt back thrust, had better extraction and increased velocity...

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## distant stalker

For something not meant to start a shit fight you have used a very emotive writing style...

Interesting articles there. I think it goes a long way towards saying the effects of.and measuring of pressure and the things that influence it is still relatively unknown. It also highlights that some of.our generally accepted pressure indicators may  not reflect the goings on as well as we  believe

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## Tui4Me

Big wild cats certainly are a whole different ball game all together.

I'll stick with my common 7mm RM I think  :Grin:

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## kimjon

Thinking back to my old life as an engineer I seem to remember that a cylindrical pressure vessel exhibits twice the force on the ends as it does on the sides. So that makes the bolt lugs the most worked surface in the action (weakest link in the chain so to say).

Now pressure is force divided by area or

P = F/A 

Therefore force equals

F = PxA

So the bigger the area (the internal diameter of the case) the bigger the force. So a small cartridge loaded to 65000psi will exhibit much less force on the lugs than a magnum case loaded at 65000psi.

Now every material has both tensile and compressive properties, and once those are exceeded its considered a fail. Most engineers build in a FOS (factory of safety) to give some room for error, so if you choose to load above a certain point you are eating into this FOS. 

Basically you can't beat the maths on these things...load it too high and it will fail eventually through fatigue.

kj

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## The Claw

I think I may have worked out Mr A's secret... He has flames painted on his rifle...  :Grin:  (see 260 loads thread)
This also supports my conclusion that he is most likely an idiot with little regard for his own/others safety for loading at excessive pressures to achieve xxxx velocity. Each to their own though, and possibly I'll be proven wrong, but in the meantime I'm happy to forego a little performance to save my life possibly...

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## Spanners

> I think I may have worked out Mr A's secret... He has flames painted on his rifle...  (see 260 loads thread)
> This also supports my conclusion that he is most likely an idiot with little regard for his own/others safety for loading at excessive pressures to achieve xxxx velocity. Each to their own though, and possibly I'll be proven wrong, but in the meantime I'm happy to forego a little performance to save my life possibly...
> 
> Sent from my HTC One X using Tapatalk 2



OMG that flame job is horrible!! Why why why???

And THAT is exactly what this thread is about
What is excessive pressure in something that does not have any pressure guidelines - sometihng completely new

You cant run to a SAAMI number as there isnt one, you can only run to signs of pressure, but if soaking your projectiles in goat piss gets rid of all the pressure signs you just had at XXX point and you can now get 10% speed more out of it before getting to that spot, then are you past the limit?
And what is this 'limit'? one that you have given yourself at some time because there isnt an industry standard? - then what if the guy next door uses tahr piss? and gets 12%? 

What about the idea for eg of a super Weatherby throat (no idea on this its just an example of what-if)
Let say your 308 can run 2900fps - crazy idea - give it SHITLOADS of freebore - 4x that of a Weatherby - get a reamer made, shove it up its bum and voila, you can now get 3050 out of it before pressure signs - unsafe? well the action will hold Magnum pressures and you;re not there, and the brass isnt getting wrecked, but your mate who can only get 2950 before wrecking brass etc is going to slap you up the side of the head as you;re faster than he can get and using 3 more grains of powder.

30-06 in a 1903 was about it 110 years ago, 300 RUM is going to blow up a gun of that construction, but in a suitable action we have something that far surpasses the ol -06
Having an open mind and thinking outside of the square/triangle/circle is whats given us all these calibers over the last 100 odd years.

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## The Claw

Yes, there are most likely tricks and secrets out there on how to get more velocity for a given pressure, but then there is also a point where these tricks have been used and only more pressure will give more velocity. If you have pressure testing gear, why not just publish what pressure you are running at then punters can make up their own mind about whether they think its safe. I for one, wouldn't touch a wildcat chambering, or take any notice of quoted velocities, without having an idea of the pressure required to achieve said results. Especially when its got well in excess of 100 gr of powder about 15cm from my face...

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## gimp

Because the numbers from pressure testing gear seem to be as good as made up??

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## Spanners

> Yes, there are most likely tricks and secrets out there on how to get more velocity for a given pressure, but then there is also a point where these tricks have been used and only more pressure will give more velocity. If you have pressure testing gear, why not just publish what pressure you are running at then punters can make up their own mind about whether they think its safe. I for one, wouldn't touch a wildcat chambering, or take any notice of quoted velocities, without having an idea of the pressure required to achieve said results. Especially when its got well in excess of 100 gr of powder about 15cm from my face...
> 
> Sent from my HTC One X using Tapatalk 2


Once again the whole point to this thread.
This new design receiver with new design case is at 87654psi
You cant even go and buy the same pressure gear and see if its true or close or anything as its no longer even being made.
You then '_make up your own mind as to whether its safe'_ - based on what information? Jimmy saying it right, or Bob saying its not?
The slow one is exhibiting all the pressure signs and thus at a brick wall, where the fast one has none of them
You have a number which is 100% meaningless as there is nothing to refer it to as its all new- its a number and nothing more, but if 87654 is a number you play in the lotto and makes you feel good, then by all means use that to '_make up your own mind as to whether its safe'_ 

One of the wildcats in my interest is low pressure ~40,000psi and pressure doesnt even start to come into it and is not quoted.
One guy can get it SMOKING along and has more data than anyone else from testing, another whos playing with it is breaking bolt lugs off after 50 rds (AR15) and cant get close with the same load data. Speedy has (lets say) 1 deg more case taper and a 20 thou longer throat- thus less initial bolt thurst and less initial pressure before the case grabs the chamber walls - something he isnt telling Slowpoke
If slow poke says he wrecks things at 40k and has to pull it back to 38k to get it to last, and Speedy says hes running 41k with no issues ,which one would you buy? The one thats at its limits and past it or the one with the performance, that surpasses it?

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## The Claw

OK, I'll have to admit that you have lost me with the first part there, but if 87654 is the lotto numbers I'm going to use my winnings to build a 5lb 375 super magnum that pushes 425gr projectiles @ 4,000 fps and has an infinite barrel life, that way I'll have something clearly superior to anything based on current information...:thumbup:

I know nothing about AR's, but if 40k psi is within the FOS (to use kj's example above) and there is plenty of reliable data on the performance version you would have to go with it wouldn't you? 

My main interest/concern is that whatever load is being touted as being superior, but within safe parameters for the given action and brass combination, is just that. If Zeek has created some new super action, surely a statement something like "has been tested to xxxx pressure for xxxx rounds without failure" and the loads developed are xxxx - 10k psi (or whatever margin is deemed prudent)  would show that in fact the velocities aren't just achieved by overloading?

If there is such an action out there, surely people aren't going to just blindly buy it/build on it without some sort of hard data?

Or have I missed the point again?

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## L.R

Spanners you really are talking shit. My 375 Lunatic is at 67,000psi and makes a 400gr projectile go 3035fps. Kiwi Greg's 375 DCM is at ???? Pressure and makes a 425gr projectile go 3080fps. 

Kiwi Greg's is at a higher pressure and therefore makes more velocity. End of story.

If its safe of not will depend on what Barnard have designed the action to take. Why don't you call them and ask if they are happy with the pressure Kiwi Greg is putting on his action insted of speculating all this shit.

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## Spanners

> ...... fact the velocities aren't just achieved by overloading?


But where is the point or max to quantify a statement of 'overloading'
Maybe the fast one is 'normal' and the slow one is 'underloaded'?

With no SAAMI data, is the person that has shot 10 rds setting the standard or the person thats shot 500rds in a better position to set it?

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## Sidney

OK I have seen this discussion going on for a while and not being an expert I would like to make a couple of observations and ask a couple of questions.

With any cartridge, whether a known quantity or not, starting loads can be reasonably easily established from already available loading data, or sensible comparision with other cartridges of similar capacity/projectile selection.... yes?

Sound reloading practice from suitable starting loads generally shows incremental increases in pressure evidenced by case head expansion, velocity spikes, increased bolt lift, excessively flattened primers yada yada...

The main issue we face as reloaders is: - to not have excessive pressure affecting our brass, as brass failure is our primary concern?

Brass is almost always the weakest part of our system.  Brass failure is something that we need to ensure that we completely avoid.

The setting back of lugs, resulting in headspace increase over time is a possibility with repeated use of hot loads and is more likely to occur with strong brass that may not show 
excessive pressure signs as readily?

However if that is occuring, we should see an increase in the signs of pressure on the brass as the headspace increases.  As indicated in Kirby Allens post referenced earlier..

So we are now back to the start.... I would assume that it is unlikely that catastrophic failure is going to occur with a single hot load with new brass, a correctly headspaced low use rifle if the hot load is not a complete cockup.

Every other situation we should have progressive brass pressure signs before catastrophic failure...

Repeated firings that do not result in the need to resize, would be unlikely to be setting the lugs back in a rifle..?

Is a strain gauge giving a pressure reading a reliable predictor for brass failure?  I am getting the impression that it is not (relative action strength, brass strength etc)

Is a strain gauge a predictor for the potential of action degradation as a result of hot loads over time?  Potentially I think it may be ..  yes?  Are the other indicators of pressure in terms of brass and increasing headspace sufficient without a strain gauge? .......most probably - but you are in effect waiting for the result rather than predicting it.... and that may be a useful result.....

Is a strain gauge a valid comparator across differing rifle setups?  Probably not from a scientific perspective, but in broader terms, experience would give some statistical probability..?

Is a strain gauge a useful tool for the comparative establishment of sensible pressure boundaries in a single rifle, (along with other indicators) or as illustrated by KG with choices for optimal powder selections?  I would think obviously the answer would be yes..

I see it as another tool, that can assist particularly in the development of new cartridges along with other existing indicators.

It is possible however to use the basics well in that process without the need for a strain gauge..  The danger in my view is reliance on data from another rifle producing x pressure with a certain load, and using that load in your own rifle without doing proper load workups.

Asking a question about pressures (from a strain gauge) because of a concern about what is seemingly a strong loading; is valid?  A response should be qualified in terms of case life, pressure signs resizing requirments, action specifications etc... but that information is hardly a commercial secret?

Help me if I am not getting it....but I think that this discussion while helpful has been being argued from differing perspectives, and neither position is completely wrong or completely right?

Yes/no?

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## Spanners

> Spanners you really are talking shit. My 375 Lunatic is at 67,000psi and makes a 400gr projectile go 3035fps. Kiwi Greg's 375 DCM is at ???? Pressure and makes a 425gr projectile go 3080fps. 
> 
> Kiwi Greg's is at a higher pressure and therefore makes more pressure. End of story.
> 
> If its safe of not will depend on what Barnard have designed the action to take. Why don't you call them and ask if they are happy with the pressure Kiwi Greg is putting on his action insted of speculating all this shit.


 22-250 and 223 WSSM run the same pressure and get different speeds for the same weight proj, as does 270 and 270 WSM 

Fact of the matter is, you;re not even shooting the same chamber/case - so thats a pretty bold statement to make

Regardless of if KG is at a higher pressure or not, can you explain why 67000 was the chosen as the final number? - genuine interest not a dig - because I keep hearing 'overloading' and want to know how we get to a line in the sand that anything over and above is 'overloaded' - This is whats this is all about; Wildcats in general without industry standard data
Was it a accurate load and left at that?
Is it max that the brass will take?
Is it max that the chambering will take?
Is it max the action will take?

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## ARdave

might seem like a dumb question but why dont they make/experiment with thicker brass to withstand more pressure for something custom?

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## The Claw

> might seem like a dumb question but why dont they make/experiment with thicker brass to withstand more pressure for something custom?


I Spose they could, but got to have a weak point so brass is probably the best thing to let go... 

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## ARdave

yea true bro. probably been experimented with already, but trying titanium 'brass' or double thickness brass surely would squeeze you a few more psi in youd think a? like if cost wasnt an issue. i supose its better for the brass to crack thank your face hahaha

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## The Claw

> 22-250 and 223 WSSM run the same pressure and get different speeds for the same weight proj, as does 270 and 270 WSM 
> 
> Fact of the matter is, you;re not even shooting the same chamber/case - so thats a pretty bold statement to make
> 
> Regardless of if KG is at a higher pressure or not, can you explain why 67000 was the chosen as the final number? - genuine interest not a dig - because I keep hearing 'overloading' and want to know how we get to a line in the sand that anything over and above is 'overloaded' - This is whats this is all about; Wildcats in general without industry standard data
> Was it a accurate load and left at that?
> Is it max that the brass will take?
> Is it max that the chambering will take?
> Is it max the action will take?


Don't know the answers to your questions, but using your example of two different cases in the same calibre, 375 Lunatic vs 375 Terminator (I really was scratching my head as to was this thread was about...:rolleyes:  ), one has stated velocity and pressure to achieve said velocity, using the same action and barrel but a different case design. If the other would post comparable data with regards to what pressure was being run then we wouldn't all be wasting time here with what ifs... If it so happens that the pressures are much the same with the higher velocity being quoted then well done to the designers of case X...

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## kimjon

> 22-250 and 223 WSSM run the same pressure and get different speeds for the same weight proj, as does 270 and 270 WSM 
> 
> Fact of the matter is, you;re not even shooting the same chamber/case - so thats a pretty bold statement to make
> 
> Regardless of if KG is at a higher pressure or not, can you explain why 67000 was the chosen as the final number? - genuine interest not a dig - because I keep hearing 'overloading' and want to know how we get to a line in the sand that anything over and above is 'overloaded' - This is whats this is all about; Wildcats in general without industry standard data
> Was it a accurate load and left at that?
> Is it max that the brass will take?
> Is it max that the chambering will take?
> Is it max the action will take?


I'm enjoying the read so far and well done for keeping it professional (no name calling etc...)

If you look at older loads say the 45/70 or similar that run at much lower pressures it would be a combination of spanners list of Q's above that lead to the pressure being specked so low (SAAMI or whatever standard was used) to protect the user in all situations, based on the cartridge and rifle that it was likely to be used in. The old Henry rifles with their brass actions wouldn't handle any more than a given pressure (the action would fail), so the calibre was made around the limitations of the rifle.

I guess what Spanners is asking is that if we make a new wildcat, then fit the rifle around that wildcat...how far can we go?


Keep up the debate...


kj

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## Spanners

That's exactly it Kimjon. 
And especially so for new cases as opposed to others that are necked up/down eyc

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## L.R

The 375 cheytac is no new round. And in NZ we are by no means the first to improve it. So there is already data with regards to velocitys for the cheytac case.

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## Spanners

> The 375 cheytac is no new round. And in NZ we are by no means the first to improve it. So there is already plenty of data with regards to acceptable velocitys for the cheytac case.


Correct - however the DCM is not the same chambering is it not?

Any reply to the 67k questions?

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## Sidney

OK seeing as my last post was to long winded.... let me have another go...

The suggestion is that good brass because it is stronger does not show the signs of pressure in a strong action.

If the failure of brass is the problem that we are trying to avoid, then what does it matter what the pressure is as long as there are no pressure signs?

If the action isn't strong enough, we should be seeing pressure signs in the brass before failure?

So 50K or 70K or even 90K is irrelevent if there is no pressure signs in the brass?

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## L.R

There is not a lot between no signs and failure on some of the hard brass.  Personally I would like a large safety margin back from the point of failure to protect my eyes, face, life if anything is to ever go wrong. If you are at the limit all it takes is a slight overcharge or high temp to cause failure. It seems a lot of people forget what is at stake if it all goes wrong.

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## Spanners

> There is not a lot between no signs and failure on some of the hard brass.  Personally I would like a large safety margin back from the point of failure to protect my eyes, face, life if anything is to ever go wrong. If you are at the limit all it takes is a slight overcharge or high temp to cause failure. It seems a lot of people forget what is at stake if it all goes wrong.


So what was the 'limit' in _your_ gun?

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## L.R

It was not taken to the "limit" as it would risk my action, brass and the person shooting it.

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## Spanners

> It was not taken to the "limit" as it would risk my action, brass and the person shooting it.


Thats the whole point of this thread, what is the limit with something that doesnt have a standard, and what signs exhibited etc to draw to that conclusion?
A line was obviously drawn, how, what, and why was it drawn there and not further up?

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## Sidney

OK so what the limit.... in your gun

Do you not follow the tried and accepted practice of loading up incrementally until the first signs of pressure and then backing off a subjective safe amount?

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## L.R

Because we are using actions and brass similar to say 338 lapua which has a safe working pressure of around 65-67k. What makes you think that it's sweet to run cheytac brass up to 88k when nothing else has a safe working pressure that high?  Have you confirmed with Barnard that they believe their action is fine to take that much bolt thrust?

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## Spanners

So a number was come about and worked to - and based on the number that was come up with, everyone else is 'overloaded'?
A number worked too with equipment that has a number of weak points.
'What if' the gear is reading 5% high - you now are ~3000psi shy of your self imposed number

The 338 LM was CIP accepted with a 250gr proj as a standard for use in 700 sized actions by the military 23 odd years ago
The fact that nothing SAAMI or CIP approved above that pressure is a pretty narrow minded approach to development.
Mentality like that from someone like Ackley would have us in a pretty vanilla work as far as calibers go nowadays

Brass and actions barely resemble what was originally on offer in circa 1989, surely we're well and truly in a 'bigger and better' world?

Where does this 88k psi come from?, its a number widely thrown around

I doubt very much if Steve would give you a number, however without bolt lug setback and/or stretch, you'd be pretty safe from a mechanics and physics point of view to say you are well within the strengths of XX action, afterall, without setback you havnt hit the yield of the material, which will more than likely be in the range of double the pressures we're talking
Steves a smart cookie, maybe a little eccentric, but no slouch. 
I'm sure he has done the lug shear calculations, I wouldnt mind doing them myself. Some calcs I've seen have a FOS of 2 in them.

In regards to bolt thrust, I presume you have cut 375 Bertram brass and seen the base of it? given what you will find in there, you will actually find that the bolt thrust will be LESS that that of using Cheytec or Gibbs brass (not that anyone uses Gibbs, but its an example of same sized case with same pressure having a big difference) due to its internal base diameter.
Thrust is easy to calculate - you only need PMAX and area the force is acting on - in this case internal area of the case head.
I think it would be moreso reduced due to its design which is probably more of an artefact from manufacturing

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## baldbob

This thread is pointless!!!!!!

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## Spanners

> This thread is pointless!!!!!!


Thanks for your valued input.
You can admit its over your head, we wont think any less of you

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## The Claw

> Correct - however the DCM is not the same chambering is it not?
> 
> Any reply to the 67k questions?


Now I'm confused? The first line of KG's 375 DCM thread says that it is a 375/408CT Improved? Sure it will have subtle differences but there should be some similarity with the results seen?

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## L.R

87654 or 88k if you like came straight from you in a earlier post.  
You make a lot of assumptions about how strong an action is and how much pressure they can take. If you read the link posted a few pages back you will see that Kirby Allen has had lug set back in an action way before double the pressures we are talking about as you suggest. Sure a Barnard will be stronger than a Rem action but it needs to be to cope with the much higher bolt thrust generated by the Chey tac case. 

You seem to suggest that as long as you are not seeing any lug setback you are safe, you may only be 500psi off this point and you would have no idea. This does not give much margin for small things to go wrong.

You have come here suggesting that KG's load is safe because no one can prove to you that it's not. Why don't you do some research and testing and prove that it is safe, a good start would be to publish the pressure figure of the load he is using.  I believe that hiding it is what is leading people to suggest he is overloading.  

Personally I am happy with mine at 67k and I have no problem with KG and his customers loading to whatever they think is appropriate.
I think in time the reasons to keep the load at more normal pressures could become apprent.

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## Spanners

> Now I'm confused? The first line of KG's 375 DCM thread says that it is a 375/408CT Improved? Sure it will have subtle differences but there should be some similarity with the results seen?


Hmmm.. not sure how to reply - obviously there are some details that are different which cant be divulged by me as its not my case design or place to do so

But are we not in a position now that 67k psi is a number selected by the shooter/builder of one chamber based on the 338LM rather than an actual pressure that is deemed safe in this configuration through, brass, action etc  signs?
I consider them different chambering to be honest as there is a difference maybe albeit subtle and a couple of other things that contribute

Which brings us back to the original topic of creating wildcats and where/how you draw the line

----------


## baldbob

> Thanks for your valued input.
> You can admit its over your head, we wont think any less of you


Not over my head wee spanny!!!! Just seems pointless I dont see what your trying to acheive here....  As you were  :Have A Nice Day:

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## L.R

Again Spanner you are assuming that you know how the cases are different. You have never had a Lunatic case to measure.

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## Spanners

> Not over my head wee spanny!!!! Just seems pointless I dont see what your trying to acheive here....  As you were


Ok - I'll make it simpler.

I get a brass mfg to make me some brass I designed in .345 Superwisbanger caliber. (or .123 Humdinger)
Get the biggest gruntiest action I can get and work some loads up as per you would with any other caliber, ladder, chrony data, measures cases, primers, action signs etc etc
When do you stop, and why - your pressure gear says 200,000psi (stupid number I know), but everything else is just sweet - no signs whatsoever of any issue.
Cases lasting multiple firings, no expansion, dont even need to FL size, everything is MINT
You fire a few more hundred rounds and still O for awesome.
Is there still room to go further or not? if not then why? and if yes, now where to you stop?

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## baldbob

You stop when you reach a comfortable pressure for the powder/brass/action/pill your using.....

Doesnt matter if your loading .223 or .375 lunitic its basic reloading practise ABCs kinda thing...

Therefore I think its pointless...

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## R93

> You stop when you reach a comfortable pressure for the powder/brass/action/pill your using.....
> 
> Doesnt matter if your loading .223 or .375 lunitic its basic reloading practise ABCs kinda thing...
> 
> Therefore I think its pointless...


I think you just confirmed the point he was trying too make Bob.

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## Spanners

> You stop when you reach a comfortable pressure for the powder/brass/action/pill your using.....
> 
> Doesnt matter if your loading .223 or .375 lunitic its basic reloading practise ABCs kinda thing...
> 
> Therefore I think its pointless...


BINGO!
If all the ABCs are correct and the pressure gear says 200k psi then for this caliber and combo etc is 200k too high?
And if yes how and why?

As much as you think this maybe pointless, I think its a good discussion

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## Sidney

+1

R93

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## Spanners

> 87654 or 88k if you like came straight from you in a earlier post.  
> You make a lot of assumptions about how strong an action is and how much pressure they can take. If you read the link posted a few pages back you will see that Kirby Allen has had lug set back in an action way before double the pressures we are talking about as you suggest. Sure a Barnard will be stronger than a Rem action but it needs to be to cope with the much higher bolt thrust generated by the Chey tac case. 
> 
> You seem to suggest that as long as you are not seeing any lug setback you are safe, you may only be 500psi off this point and you would have no idea. This does not give much margin for small things to go wrong.
> 
> You have come here suggesting that KG's load is safe because no one can prove to you that it's not. Why don't you do some research and testing and prove that it is safe, a good start would be to publish the pressure figure of the load he is using.  *I believe that hiding it is what is leading people to suggest he is overloading. * 
> 
> Personally I am happy with mine at 67k and I have no problem with KG and his customers loading to whatever they think is appropriate.
> I think in time the reasons to keep the load at more normal pressures could become apprent.


Sorry - should have been clearer.. 87654psi was a number I pulled out of my arse, but 88k is a number I have seen mentioned a few times as to the strength of the brass - was just wondering where that number came from thats all, though from your reference to 88k and not 87654 that you were using it as a figure.

I did a fair bit of dicking around with cases and the gun etc, 
As far as pressure goes, I completely avoided the topic via strain gauge as I give it little merit regardless of brand in regards to a number. I ran racecars on dynos for years, and know the differences between machines - and its the same situation.
We're not dealing with something thats been shot for 50 yrs in the same construction of brass and receiver and thus pressure really has no influence IMO
If this case was designed before any 'magnums' were CIP or SAAMI approved, would you load to 50k psi and call it quits? of course not - thats where and how magnums were developed. Are we not talking about a magnum magnum now? if so then why are we limiting things through a set number from 30 years ago rather than working with the case to see where it goes?

If you can load the same case 5 times without FL sizing, primer pockets are tight as a tiger and there are none of the ABC signs from common sense reloading, then pressure of XXXpsi means what?
Back to a point I made earlier - overloading is loading more than a standard - the _standard_ appears to have been set by pulling a number from thin air or from a completely different caliber 1/4 of a century old

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## Spanners

> Again Spanner you are assuming that you know how the cases are different. You have never had a Lunatic case to measure.


Correct yes - but are you stating they are the same?

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## baldbob

> I think you just confirmed the point he was trying too make Bob.


Well four pages of fanny flapping and how come I got it in two sentances?????

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## Spanners

> Well four pages of fanny flapping and how come I got it in two sentances?????


Cos I started with 'I'll make it simple'  :Grin: 

Did you read the rest though as I feel I said the same thing 10 times lol

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## L.R

The problem you have spanners is you have no idea of the failure point of the action.  If you don't trust the strain gauge why don't you buy a pressure transducer from oehler and use that to determine you actual pressure, then go back to barrel, action and brass mfgs and ask them if it is within its designed safe operating range.

Yes putting a transducer in all but destroys the barrel for future use but, if you want to push the limits and then sell to customers then sacrificing a barrel should not be an issue.

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## Sidney

How many other commercial action manufacturers have published the failure points for their actions? Or barrel manufacturers for that matter?

Is pressure signs in brass not evident before damage to actions and barrels?

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## L.R

Not in Kirby's case in the link. 

 I think it would be the duty of an action manufacturer to give a safe working pressure of their action.

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## Sidney

Well actually he had increasing bolt lift problems... as a result of increasing headspace... that would be pressure and brass wouldn't it

well..... which came first....??

brass signs or headspace

----------


## Sidney

> Not in Kirby's case in the link. 
> 
>  I think it would be the duty of an action manufacturer to give a safe working pressure of their action.



So who does?

----------


## L.R

No the bolt lift problems came from the lug setback, so the brass signs came as a result of the action damage. 

I don't know of anybody who has asked. I'll call Barnard tomorrow and ask them.

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## Sidney

This whole thing seems a bit chicken or egg to me...

I think that applying an arbitary pressure across all actions/barrels/calibres as being a safe do not exceed could be sensible for the great unwashed... but clearly it is not necessarily relevant to individual rifles.  How do you deal with 96 mausers vs Barnards for example...

Even though hard strong brass in a strong action may be more light-switch moving from safe to not, the principles are still the same.  I would suggest backing off a little more than other well documented options in this case once first pressure signs are reached.

I have a hard job believing that cases fired 5 times and not having required resizing, contain loads that are causing damage to actions in spite of whatever pressure that they are running...

I also believe that it is unlikely that a whole new class of firearm performance has been unearthed as a result of totally original thought, requiring secrecy and "IP" protection the like of the "you copied my silencer design" dramas of the recent past...

If you want to be an original thinker and still benefit from it, not much is gained by trying to lock it down and protect it.  You're far better off link your brand with the product and get it out there so that whatever it is becomes always linked with you.... the microsoft saturation model :Yaeh Am Not Durnk: 

Don't know anyone with a dakota proprietory calibre...... :Yaeh Am Not Durnk:

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## L.R

I am not saying anyone is doing damage to their actions here, I'm just asking how you know they can handle these higher pressures safely. 

I think it's one of those situations where you should do as you feel is safe.  If that's 80k for you that's fine. It's not for me until someone can prove that all the components are safe at that pressure and have a good safety margin remaining.

----------


## distant stalker

> Sorry - should have been clearer.. 87654psi was a number I pulled out of my arse, but 88k is a number I have seen mentioned a few times as to the strength of the brass - was just wondering where that number came from thats all, though from your reference to 88k and not 87654 that you were using it as a figure.
> 
> I did a fair bit of dicking around with cases and the gun etc, 
> As far as pressure goes, I completely avoided the topic via strain gauge as I give it little merit regardless of brand in regards to a number. I ran racecars on dynos for years, and know the differences between machines - and its the same situation.
> We're not dealing with something thats been shot for 50 yrs in the same construction of brass and receiver and thus pressure really has no influence IMO
> If this case was designed before any 'magnums' were CIP or SAAMI approved, would you load to 50k psi and call it quits? of course not - thats where and how magnums were developed. Are we not talking about a magnum magnum now? if so then why are we limiting things through a set number from 30 years ago rather than working with the case to see where it goes?
> 
> If you can load the same case 5 times without FL sizing, primer pockets are tight as a tiger and there are none of the ABC signs from common sense reloading, then pressure of XXXpsi means what?
> Back to a point I made earlier - overloading is loading more than a standard - the _standard_ appears to have been set by pulling a number from thin air or from a completely different caliber 1/4 of a century old


This should have been your first post and things would have stayed on track better. The signs your mentioning would suggest pressure is ok
 You yourself mentioned how hard it is to know pressures. Is it then possible to know accurately the strength of the action then know the pressure of the load then factor in the safety buffer or is it all based on experience based estimates? If it is left to estimates then until that action is fired x amount of times at x pressure and examined you won't be able to know. I would like a good safety margin

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## Sidney

I wouldn't have a clue what pressures I run my rifles at.  Most are sorted at 2 grains less than first signs of pressure on new brass.  (I don't load more than 55grains of capacity at the moment)  Most of my loads exceed listed maximums from reloading manual and supposedly max safe loads.  My GS custom rounds exceed by quite a margin without pressure signs.  Why is that approach not sufficient for any workup?

Will a 70K psi figure released from somebody's strain gauge mean 70K.... or it could be 85 or 55 in reality?

If I blow up one action in testing to determine failure point, on what basis can I use that information to realistically establish the safe working load of other actions produced by the same manufacturer... whats the probability of my sample of 1 reflecting the average population all all other production for that action from that manufacturer...?

Some actions are known to be stronger than others.... how have we established that in the past....??  By load development in the action... whats changed?  The only thing you don't know with a new cartridge is the starting point, but that can be worked out.... after that it all gets really similar?

Build your own safety margin in......

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## Spanners

> The problem you have spanners is you have no idea of the failure point of the action.  If you don't trust the strain gauge why don't you buy a pressure transducer from oehler and use that to determine you actual pressure, then go back to barrel, action and brass mfgs and ask them if it is within its designed safe operating range.
> 
> Yes putting a transducer in all but destroys the barrel for future use but, if you want to push the limits and then sell to customers then sacrificing a barrel should not be an issue.


Steel > Brass - simple mechanics 
I'd put my left nut on the fact the there hasnt been and action failure ever without brass failure - and if you are well off brass failure then you are well off action
Its like wrapping an egg in bubble wrap - if the egg survives you're not going to nuke the wrap, you'e going to nuke he egg first.

I;ve looked for an Oehler for my own interest, cant buy one as havnt made them for years - maybe Mr Oehler has canned the strain gauges due to the downfalls - after all - he admits to most of them.
As far as using them to determine an _actual pressure_ - *useless* as there is no calibration - ever talked to barrel, action and brass mfgs and asked them what their PMAX is? I'd say no, and you'd get a reply of no. You have brass/barrel and you do what you will with them. Hell - most main firearms mfg dont even proof barrels, guaranteed any blank is not done.

Universal receiver for pressure testing -yes - I'm in negotiations at the moment for one actually - before I lay down that cash, I'm going to be sure I can ACTUALLY have it shipped to me - State dept pending.

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## Spanners

> This should have been your first post and things would have stayed on track better. The signs your mentioning would suggest pressure is ok
>  You yourself mentioned how hard it is to know pressures. Is it then possible to know accurately the strength of the action then know the pressure of the load then factor in the safety buffer or is it all based on experience based estimates? If it is left to estimates then until that action is fired x amount of times at x pressure and examined you won't be able to know. I would like a good safety margin


Maybe I know what I'm thinkging but its not getting out, but I feel like I have repeated the same info in that post a number of times.

I;m the sort of person that will call BS on anything unless it makes mechanic sense as far as numbers and calcs go, or I have witnessed it and seen it for myself to the quandary, however Ill also admit any time I'm proven wrong and will also sit back and go 'holy shit - you're right and it works'
If you can better yourself and learn something you are onto a winner, if you can _change_ your prospective totally based on real world in your hands info, then I think you win even more.
I had a  'Holy shit - you're right' moment the other week end - and I considered myself towards the end of what I could learn as far as loading goes to be honest - its great to be humbled, and to also be a part of 'you're the only person who knows this' and to see and touch WHY it works

I'll admit I was sceptical on KGs loading of the 375 based on the rhetoric I have read here. However after doing the investigation work on the cases etc, and now that the fact that 67000psi is a number to be used as the benchmark for his 'overloaded' cases as set by someone elses belief, that KG is ahead on paper and in his real world development.
I'm not goign to buy a gun from either party in the fight, however you come up with a caliber/loading etc that works and ticks all the correct ABC boxes, and you;re ahead of the pack, you get a pat on the back - regardless of who you are.
If you want to bash the opposition because you're coming 2nd in the race, then you can only expect a few swing back - no?

The whole point of this is a new case with no info/data - it has turned into the 375 big dicks competition, which isnt bad as it is an example of exactly the topic at hand.
You can do the math on action/lug strength, the number you get whether raw or with a FOS will surpass the brass strength - simple mechanics again.
The fact that  the traditional (I steal from Bladbob) ABC signs of pressure are not being exhibited in the brass then you havnt hit the brass's failure point, and more than likely far from it.
I will note that where you WILL run into excessive stress of an action is when is with catastrophic brass failure in the forum of a case head separation.
In this situation, you are applying all the force to the action. 
There is a good book on the 1903 which goes into alot of the action and cartridge development - tests they did with turning barrels down to almost waffer thing between the chamber and OD, deforming cases to MAKE them fail and induce casehead seperations and thus load the lugs, different heat treatments etc - all VERY interesting stuff. They TRIED to blow guns up on a regular basis - all this stemmed from 100+ yr old heat treatment processes where it was no more scientific than looking at the colour of the steel with crap lighting. We are FAR more advanced in this age.

Maybe the guy who has fired 500+ rds in the chambering and has played with a couple of different reamers etc has learnt someone over the guy that orders a reamer off the net and fired 10rds to draw his conclusion?

----------


## Spanners

> I am not saying anyone is doing damage to their actions here, I'm just asking how you know they can handle these higher pressures safely. 
> 
> I think it's one of those situations where you should do as you feel is safe.  If that's 80k for you that's fine. It's not for me until someone can prove that all the components are safe at that pressure and have a good safety margin remaining.


And thats the whole point of this thread.. AGAIN
Its not a matter of 'feeling; whats safe, its about getting the most out of a new cartridge with no standard info
Who, what, why and when to stop?

Damn near Ford v Holden... :Yaeh Am Not Durnk:

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## Toby

Load up the highest pressure load you can think of put in your gun tie a string to your trigger stand back a bit and if it fire it off, if your gun blows up its too high and your gun cant handle that, then get a a new gun and try it again but lower the pressure how ever you do that(different powder amounts? idk) then try it again, if gun blows up then try again.

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## Spanners

> Load up the highest pressure load you can think of put in your gun tie a string to your trigger stand back a bit and if it fire it off, if your gun blows up its too high and your gun cant handle that, then get a a new gun and try it again but lower the pressure how ever you do that(different powder amounts? idk) then try it again, if gun blows up then try again.


Yeah.. - not the most scientific way of goign about....

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## Toby

Should work though

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## L.R

However it beats the science you are using spanner. Ignoring the strain gauge and trying to tell others they are just under loading. That may be the case, but you have no idea of the brass or action yield points so you just don't know how safe it is?  This is not ideal if you want to sell it to customers.  Also have you considered the massive reduction in therotical barrel life that that extra 20k will give you?

----------


## Toby

I dont know much(anything*) about this stuff but just wondering what does the higher pressures offer? does it make the projectile faster offering better accuracy or what?

----------


## Toby

Is pressure signs mean like the neck splitting? When I got my .308 it came with a bunch of homeloads a few dont chamber and then a few get spilt necks when I do shoot, but the ones have shot group have good grouping and they knock the shot out of deer. idk why some dont fit, I have been told it could be because the were shot through another rifle first???

----------


## Spanners

> However it beats the science you are using spanner. Ignoring the strain gauge and trying to tell others they are just under loading. That may be the case, but you have no idea of the brass or action yield points so you just don't know how safe it is?  This is not ideal if you want to sell it to customers.  Also have you considered the massive reduction in therotical barrel life that that extra 20k will give you?


Wooo - hold up - noones running 88k
If barrel life is an issue when you're poking $1.50 worth of powder and $4-5 pills down the tube, with $4k of scope on top and a $6k range finder sitting beside you, then I think you maybe in the wrong game.

How can a strain gauge be used to determine its safe?
Lets say in a moment of fantasy, that the pressure is 100% correct, you have a magic number of what that pressure is in the fired case- now what?

You realise that if you have to use a FL sizing die or any die, then the brass has past its elastic limit and yielded? this happens with almost EVERY rifle caliber from the last 100 or so years.
You would agree that if you can fire a case 5 times without FL sizing, that you are below the yield point of the brass and operating within its elastic limit?

----------


## L.R

But Spanners if this brass acts the same as all brass in all calibers has done for the last 100 years then why is it safer to run to a much higher pressure?

----------


## Spanners

> But Spanners if this brass acts the same as all brass in all calibers has done for the last 100 years then why is it safer to run to a much higher pressure?


_if you can fire a case 5 times without FL sizing, that you are below the yield point of the brass and operating within its elastic limit?_

----------


## L.R

Yes but how far bellow you don't know. You also don't know at what point you will start damaging the action. This is what I keep trying to say, but all you can say is its not failing YET!

----------


## Spanners

> Yes but how far bellow you don't know. You also don't know at what point you will start damaging the action. This is what I keep trying to say, but all you can say is its not failing YET!


The whole point is you havnt even reached the elastic limit of the brass (something that happens in saw a RUM or WSM every firing)- the action is a shitload stronger to begin with

----------


## L.R

In Kirby's example they didn't reach the elastic limit of the brass until the action was damaged.

----------


## DAF

is there not a point where the pressure it too great that the steel used for the barrel / action loses its elasticity?
ie when the strain is beyond the threshold capacity of metal that it’s molecular or the atomic structure changes bringing a sort of deformity in the structure of the metal weakening/fracturing it?
I have read somewhere that this another reason for some of the pressure limits.

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## Spanners

> In Kirby's example they didn't reach the elastic limit of the brass until the action was damaged.


Huh? The elastic limit of the brass is reached on most calibers every time you fire, thus the need to full length size as the brass has yielded - there is no mention there about sizing of cases??

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## Spanners

> is there not a point where the pressure it too great that the steel used for the barrel / action loses its elasticity?
> ie when the strain is beyond the threshold capacity of metal that it’s molecular or the atomic structure changes bringing a sort of deformity in the structure of the metal weakening/fracturing it?
> I have read somewhere that this another reason for some of the pressure limits.


Yip - the yield point/yield strength
Stress is proportional to strain and is a straight line with the gradient of the modulus of elasticity (IIRC), until it reaches yield strength in which permanent deformation occurs.

----------


## L.R

Spanner if you need to full length size every time you fire the case it just proves you load to hot.  What Kirby clearly says is that the hard brass like Lapua, Jamison ect will not show pressure signs until you are well into dangerous teritory, in this case it set back the action lugs in a big way before the brass showed signs of pressure.  Now are you saying Kirby is wrong and this can't happen because you say so?

----------


## The Claw

Ok, so my 20 tactical brass had been fired 5 times, never been full length sized but started dropping primers... I have since reduced the load, still haven't full length sized. How does that fit into this argument? 3 other rifles I know of that have been chambered using the same reamer and the same barrel and factory Lapua brass, neck turned the same as mine won't hold a primer for 1 firing at the load I had been running initially with no issues (approx 2k rounds fired). How does that fit into this argument?

Sent from my HTC One X using Tapatalk 2

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## Spanners

FYI

Barnard P-Chey is made of 4340 hardened to 38Rockwell C
Yield strength of ~165,000 psi

----------


## The Claw

> Ok, so my 20 tactical brass had been fired 5 times, never been full length sized but started dropping primers... I have since reduced the load, still haven't full length sized. How does that fit into this argument? 3 other rifles I know of that have been chambered using the same reamer and the same barrel and factory Lapua brass, neck turned the same as mine won't hold a primer for 1 firing at the load I had been running initially with no issues (approx 2k rounds fired). How does that fit into this argument?
> 
> Sent from my HTC One X using Tapatalk 2


3 of the 4 rifles use Tikka 595 actions & the other is a vixen. All done by the same gunsmith, and a very good one at that...

Sent from my HTC One X using Tapatalk 2

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## Spanners

> Ok, so my 20 tactical brass had been fired 5 times, never been full length sized but started dropping primers... I have since reduced the load, still haven't full length sized. How does that fit into this argument? 3 other rifles I know of that have been chambered using the same reamer and the same barrel and factory Lapua brass, neck turned the same as mine won't hold a primer for 1 firing at the load I had been running initially with no issues (approx 2k rounds fired). How does that fit into this argument?
> 
> Sent from my HTC One X using Tapatalk 2


FL sizing was just an example of yield of the brass
If the primer pockets are opening up, then obviously its past point of yield
Not sure how it fits in to be honest LOL

----------


## Sidney

Yeah but dropping primers is a brass pressure issue too... enlarged primers pockets...

I have a hard job believing that there were no other signs in the Kirby example... before damage occurred... but we are not told

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## Spanners

So with a receiver (Barnard for eg) with a yield of ~165k, appropriate sized lugs etc and this new chambering and brass ( take your pick or make one up) whats the stop point and what process do we go about getting there?
Lets say brass is good for 88k psi as per the mfgs say so
If you get to 70k psi and everything is indicating sweet, then why not 75k?, 80k? if all good there also, after all, this aint your grandaddies deer huntin' rifle

Arnt we at the same stage back in time when 50k psi was PMAX and then with the advent of stronger actions/materials etc, we saw a new class of cartridges at 65k psi

----------


## L.R

Spanner are you suggesting that the lug shear point on the Barnard it at 165k pressure in a Chey tac case?  Using your extensive reloading knowledge, what do you think is a reasonable pressure to run 375 cheytac brass in a Barnard action at?  Do you think KG is over 80k pressure?

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## Spanners

No - simply stating the yield of the receiver is ~165k psi as a mechanical property
I could do the shear calcs in about 10 mins with some dimensions - I have some drawings for the Barnard somewhere here, but I dont think it has bolt and lugs on it

I can find no mechanical reason as to why 80k would not be a pressure easily obtainable and run as long as you are within normal signs with the brass (as much as I hate using a pressure number as limit/reference) however the chambering may start to exhibit the signs at 75000 or less... or more... The point at which this happens is unknown to me right now.

With an action of suitable strength, why cant modern strong brasses like Lapua small primer 308 etc be run to the same signs you would say Winchester; if the action is not an issue and you're not exceeding the brasses limitations, then what reference does pressure actually have other than a final figure?
The point of the brass is to be able to run it harder - thats why they make it

Do I think KG is over 80k? *100% definitely NO*
I could guess at a number, but it would be only that, however the brass shows no signs after 5 firings and having never been FL sized still chambers, there is no measurable expansion and the primers are snug as a bug. Maybe a couple of grains more powder will change things and it will hit a brick wall, maybe there is room for 5gr more and the cases just require a body bump?
Only more testing will say how much if any headroom is there, and if the final numbers say 72k or 82k, then so be it

----------


## Spanners

Out of interest, whats the water cap of your chambering?

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## L.R

As you say the brass has been designed to take 88k. It may not show pressure signs till this pressure, you don't know as you haven't seen any. So you could be subjecting your action to this much pressure and you don't know.  Now you have stated that you see no mechanical reason why the action won't stand up to this, however you have no numbers to support that and at this stage you are just guessing. The action may well take that pressure I'm not sure but I know if I was going to push the limits of something I would like to know at which point failure is likely to occur. 

You seem to have no regard to reasonable safety factors, in fact you seem to ignore the point, running at just a few k psi below the failure point of the brass seems like a big risk with little reward.  Safety factors exist because shit does go wrong, and when it does without saftey factor it can cost lives. 

For me I will keep my ammo bellow 70k, I don't believe that the chey tac case shot out of a Barnard action is some new super round that is safe at 10k or more than other modern well designed magnums. The fact is that the 375 chey tac case and strong custom actions are a combination that has been used for several years now, for KG to be the first to discover that it is safe to push way above the accepted norms seems hard to believe.

Like I have said many times, if you are comfortable shooting you ammo at this pressure you are free to do so it doesn't effect me, I just don't think you should be telling people it is safe to do so when you certainly do not know all the facts.

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## Spanners

> As you say the brass has been designed to take 88k. It may not show pressure signs till this pressure, you don't know as you haven't seen any. So you could be subjecting your action to this much pressure and you don't know.  Now you have stated that you see no mechanical reason why the action won't stand up to this, however you have no numbers to support that and at this stage you are just guessing. The action may well take that pressure I'm not sure but I know if I was going to push the limits of something I would like to know at which point failure is likely to occur.


As mentioned before, given the mfg receiver specs we're in a way different league to a 700, so why are limiting ourselves to those specs?
Hell when eveything was on Lee Enfield, and 1903 actions, noone would have ever dreamed of putting a WSM or RUM through it.
The advent of technology and evolution gives us the equipment, materials and processes that far surpass that of 40 yrs ago.
Do you have numerical data to say that 67000 psi is safe? what bolt thrust is generated and shears involved? - I doubt it
What happens when some idiot build a 375/408 on a 700 and  uses the justification that its 338 pressures? - not even apples and oranges




> You seem to have no regard to reasonable safety factors, in fact you seem to ignore the point, running at just a few k psi below the failure point of the brass seems like a big risk with little reward.  Safety factors exist because shit does go wrong, and when it does without saftey factor it can cost lives.


I have a big regard for safety factors - you;re making presumptions that the pin is out of the grenade where all logical testing proves otherwise.




> For me I will keep my ammo bellow 70k, I don't believe that the chey tac case shot out of a Barnard action is some new super round that is safe at 10k or more than other modern well designed magnums. The fact is that the 375 chey tac case and strong custom actions are a combination that has been used for several years now, for KG to be the first to discover that it is safe to push way above the accepted norms seems hard to believe.


What if I told you it was at 70k (not saying it is or isnt) - would your opinion change?
How did magnum design come about when the norm was 50k psi, and why cant their be another step - there was from black powder to smokeless, and from 35k to 50k also, so WHY are we at a point where you CANT develop anything further?
I quote Mr Bertram _'why run your new V8 on kerosene?'_




> Like I have said many times, if you are comfortable shooting you ammo at this pressure you are free to do so it doesn't effect me, I just don't think you should be telling people it is safe to do so when you certainly do not know all the facts.


You seem to be hung up on the fact that where you are for whatever reasons is safe (which is totally fine) but anyone else is wrong.
You have no facts either - only what you are comfortable with based on opinion or superstition. 
Why cant the natural progression of development continue - why all of a sudden has hundreds of years of cartridge development stopped in 1989 (338LM)  - a long time before big custom actions and brass - which bear little resemblance to then.

I dont mean any of this to come across as a dig as I am genuinely interested in all things guns and this 375 topic and another wildcat have taken my interest.
Both are old and new ideas clashing.
I strongly believe we are at another step in performance and testing and physics will confirm or reject this
As I mentioned before, I'm in negotiations for a Universal receiver for pressure testing so more real data may become avail in the future.

If you could take a pic of the action lugs and bolt - square on for both, and side on for the bolt , I'll draw some points to measure on the pic
Send the info back and I'll do a shear analysis on it.
I have no doubt from rough calcs I've already done, that you will damn near vaporise brass before you have an action issue.
Remember - this aint grandaddys deer huntin' rifle  :Have A Nice Day:

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## L.R

67k is not something that has been run in a case with a .640 case head for 30-40 years Spanner. 
The 408 and 375 chey tac were designed to run at normal magnum pressures of around 63k.

I know that my action is safe at 67k because KG has done the proof pressure testing for me :Grin: 

No seriously Greg Duley has loaded it higher to check pressures and signs and found them, so is happy that we are safe at 67k.

I really just don't get why you guys think that you have stumbled on something that other experts in the field have not been able to do to any degree.
All you have done is push the brass and action further into the danger zone, this is not something new, idiots have been doing it for years.

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## tui_man2

im back.......................

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## gimp

Hey

What's up?

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## L.R

> Hey
> 
> What's up?


Pressures :Pacman:

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## gimp

Nah mine are all good bro


I know because


wait


fuck

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## Spanners

> 67k is not something that has been run in a case with a .640 case head for 30-40 years Spanner. 
> The 408 and 375 chey tac were designed to run at normal magnum pressures of around 63k.
> 
> I know that my action is safe at 67k because KG has done the proof pressure testing for me
> 
> No seriously Greg Duley has loaded it higher to check pressures and signs and found the, so is happy that we are safe at 67k.
> 
> I really just don't get why you guys think that you have stumbled on something that other experts in the field have not been able to do to any degree.
> All you have done is push the brass and action further into the danger zone, this is not something new, idiots have been doing it for years.


Little bit of a twist of what I implied there.
You originally said your 67 was based off the LM pressures......

Hey if you've gone higher, found the pressures and come back, then sweet as - not discounting that at all.
But broaden your outlook a bit and consider 'what-if' someone is doing something different that works....

What about Carlocks +P - go back 4-5 yrs or whatever - the 338 Edge has progressed has it not?

Once again you're 'presuming' the pins out of the grenade, maybe you're not shooting the same chamber, and maybe something else isnt been given away just yet.

This is all in regards to the 375, but as a broader picture the discussion of a development still has validity.

Are you wanting to go through with shear analysis?

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## Kiwi Greg

> The fact is that the 375 chey tac case and strong custom actions are a combination that has been used for several years now, for KG to be the first to discover that it is safe to push way above the accepted norms seems hard to believe.


You are guessing, without knowing my case capacity, seating depth, throat design, bullet coating..........

I was told by Daniel (CE Bullets) earlier this year when I was shooting the 400s out of my 375 Terminator that I had the second highest velocity that he knew of at that time.

That case was "over 67500 PSI" as well, but it is on the same action & barrel combination (7.8 exit twist) with Lapua brass that survived 15+ firings.

There is very little data out there with the large 375 CE pills simply because very few people have shot them.

This is mainly due to barrel twist rates & people willing to think outside the square, as I did when I asked Daniel to make the 425s for me.

I'm not particularly happy with being singled out & accused of over loading a case when mine is different to others.

Not to mention there is basically no other load data available for the 375, 400, 425 pills shot out of an imp Cheytac case like mine.

Here is something to think about.

My CE 350s run at 3350 FPS out of a 32 gain twist barrel with Retumbo with what I judge to be similar pressure to the 400 & 425 pills.

Kirbys 375 Allen magnum data on his site with a 30" barrel & 350 SMKs states 3300fps with Retumbo.

So if you are going to continue to accuse me of over loading to the extent that you are, I suggest you talk to Kirby as well........

There is a very good chance that the DCM has a greater capacity than the 375 AM.

You can choose to run your loads at what ever pressure you are comfortable with, as can I.

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## Cyclist

Nobody here is thinking far enough outside the square - brass is gay, want more speed throw away the brass, buy a yellow bastard and toss a 250gn pill at *3850*fps.  If you build a complete system around max velocity and specify an action to take the bolt thrust you are sorted.  

Shoving big cases into rem's etc all seems a bit like boy racers putting kits on nana's old mitzi to me - its never going to be a race car, if you want a race car go build an effin race car...  

As for the universal reciever I suspect that building one would be easier than importing one (and paying for it)
Big block of steel, bore hole through and thread both ends - front one gets the barrel with extra long tenon (with savage style barrel nut for headspace) back end gets a breech plug (2 inch HT bolt with fine thread should hold a few kpsi).  Firing pin drilled through the bolt centre only needs to float free and project just past the end of the plug in either direction, simple spring loaded striker to fire the round - hint dont stand behind it if a primer pops, could possibly put in a safety feature like a curving up bracket behind to send it skywards.  If you want to explore MAAAAX pressures chamber the barrels deep so cases fit flush like a pistol, headspace by winding the barrel down onto the plug.  Sorted

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## BRADS

> Load up the highest pressure load you can think of put in your gun tie a string to your trigger stand back a bit and if it fire it off, if your gun blows up its too high and your gun cant handle that, then get a a new gun and try it again but lower the pressure how ever you do that(different powder amounts? idk) then try it again, if gun blows up then try again.


 @Toby did you try this yet?
This thread made interesting reading.


Sent from my iPhone using Tapatalk

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