Thread: Remington 700 Sako and M16 extractor conversions

Originally Posted by Greg Duley

I spent quite some time with the guys in the Nosler lab learning all the tricks of the trade.

When were you over at Nosler??

There is a couple of lines missing in my post... dunno what happended there
That last bit was in reference to primers

I saw an interesting vid which I will see if I can find later,
It showed how one of the big manufactures pressure tested,
They used reference ammo supplied by saami to set a baseline then in a hermetically controlled room loaded and tested their own. Quite a cool setup


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Well after sifting through 40+ pages of verbal abuse and personal attacks (I forgot why I left AR alone) we find: "there is no "After Installation" calibration of the strain gage system. To the best of my knowledge, this is true for ALL methods of chamber pressure measurement. I challenge anyone to provide a clean calibration procedure for any measure of chamber pressure in a rifle" from Dr Oehler - interesting

We then have a best possible situation of: "But for most users who pay close attention to the Set-Up and follow the directions the average variance would typically be(5%) with a Range from 57.0Kpsi <-> 63.0Kpsi" and this is starting from a calibration point of... oh thats right we dont know As someone who has worked in the measurement and testing industry that kind of "accuracy" is simply and utterly smoke.

I dont know how you could use this system to accurately or even roughly compare 2 barrels in the way that Greg suggests, this is where I have perhaps been a little unkind to De Oehler in that he states on one of the threads that the system is designed as an analytical tool for Lab use and is not designed for Reloaders (fair enough!). Dr O's response to the range of variance mentioned above "That's much better than thinking you are at 50K and actually be exceeding 75K" which suggests to me that is where he places his confidence in the machine when used in uncontrolled situations such as someones garage or workshop.

One of the more coherent threads on the topic below - have a search there for more information than you ever wanted to know about pressure testing and its inability to be pinned down or compared!

UNIVERSAL RECEIVER - Topic

You have your 5-8% IF everything is setup perfect, then a 'fudge factor' based on the barrel material

So by the time you add up all the variables, you're at what.. 20%?


Have a read though.. there are some very interesting points as to why NOT to add powder to get mfg book speeds

We need a rubbing the hands together in anticipation smiley

Sorry, been away hunting for a few days.
Well, we've used the Oehler ballistic laboratory extensively for a number of years now, across a wide range of calibres, both factory and wildcat. We are using it on barrels with a straight cylinder chamber section so the wall thickness can be measured precisely. We have found the results both consistent, common sense and matching reliable sources we trust. We have never seen an anomaly that leads us to believe the system doesn't work, so long as you are meticulous with the inputs.
Please do tell us what system you think is better for our purposes?

Originally Posted by Greg Duley

Sorry, been away hunting for a few days.
Well, we've used the Oehler ballistic laboratory extensively for a number of years now, across a wide range of calibres, both factory and wildcat. We are using it on barrels with a straight cylinder chamber section so the wall thickness can be measured precisely. We have found the results both consistent, common sense and matching reliable sources we trust. We have never seen an anomaly that leads us to believe the system doesn't work, so long as you are meticulous with the inputs.
Please do tell us what system you think is better for our purposes?

Now I'm rubbing my hands together in anticipation. Look forward to hearing the internet experts and what system they recommend.

I dont doubt its one of the best systems around for mere mortals of getting a pretty good idea of pressures run.
But as said above measurements,inputs and placements would have to be spot on and then you still have the fudge factor.

I would still put money on two different people with two different "Oehler ballistic labs" getting different numbers from the same rifle and load using there own measurements and placements and "fudge factor"

So ... copper crushing is useless,brass to variable,strain gauge.. well thats no good,chronys? na... most arnt reliable ,maufactures of loading manuals use the pre mentiond so chuck them in the bin ,I dun no I guess if we reload we're just fucked then.

Ignorance is bliss Not having any fancy tools Il continue to load up to sticky bolt lift and then back off a bit safer than fact fed blue box in my rifle.................... shouldn't have to bash the bolt handle up with factory ammo

Originally Posted by veitnamcam

I dont doubt its one of the best systems around for mere mortals of getting a pretty good idea of pressures run.
But as said above measurements,inputs and placements would have to be spot on and then you still have the fudge factor.

I would still put money on two different people with two different "Oehler ballistic labs" getting different numbers from the same rifle and load using there own measurements and placements and "fudge factor"

You are probably right but the same person using the same gear and taking all the measurements themself with plenty of reloading and rifle experiance and prgrams to compare with would have a very good idea how to read the results...

The same could be said with wheel alighnment machines... chasis measureing gear.... Numbers can be fudged or missleading with things are not done right.

I am sure with that gear and the right operator you will be a lot closer to knowing what the preasure is than going blind and relying on brass preasure signs

Also if you have put hundreds of rifles across a strain gauge and correlated the results with physical signs of pressure, sticky bolt lift, ejector stamps etc with the results, and generally exercise caution. Surely this experience would stack up and count for something?

As a tool for 'stopping at XXXpsi' or 'this load is XXXpsi' its useless as there is no reference or calibration - thus the issue

How can you quote a number or advise someone that their load is too hot??
Thats exactly whats been going on.. "the Oehler said this, and your load is dangerous"

This discussion has been going on for 10 YEARS on Accurate Reloading, as has the 'add powder till you get book velocity' being total bollox

As a tool for 'stopping at XXXpsi' or 'this load is XXXpsi' its useless as there is no reference or calibration - thus the issue

How can you quote a number or advise someone that their load is too hot??
Thats exactly whats been going on.. "the Oehler said this, and your load is dangerous"

This discussion has been going on for 10 YEARS on Accurate Reloading, as has the 'add powder till you get book velocity' being total bollox

Do you have a stutter?