Thread: Wilcats and Pressure

Originally Posted by L.R

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?

Originally Posted by R93

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?????

Originally Posted by baldbob

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

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

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

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.

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?

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.

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

Originally Posted by 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.

So who does?

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.

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

Don't know anyone with a dakota proprietory calibre......

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.

Originally Posted by Spanners

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

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......

Originally Posted by 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.

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.

Originally Posted by horihunter

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?