I see here on a few post where some people are shooting their rifles up around 68,000 and 70,000. I don't know if that psi or cup??? My question is what's the Maximum pressure to shot your firearms? I know every caliber is different, so where can someone find the maximum pressure for a certain caliber?

Thanks.

Scratch

Sporting Arms and Ammunition Manufacturer's Institute Inc. (SAAMI) sponsors a set of standards for most factory cartridges. Please note that you can only guess the maximum pressure of a particular load through software or hand calculations. There is no way to measure the actual pressure of your gun without the lab instrument (pressure barrel, etc.). Have fun.

Your post stating that people are loading to 70,000 PSI only reminds us that there are a lot of crazy/stupid/ignorant people in this world who have no idea of what the word safety means.

Never exceed printed, tested, data, from reliable sources, such as the bullet and powder makers. The life you save may be your own.

Regards DLM

For some listed data:don't get even near them!
My expierience.

Hugh.

It doesn't matter to me what the pressure measures to be, I care about at what load something goes wrong.

I have incramentaly overloaded 33 different calibers, just to see what would happen. In some calibers I repeated the process spending hundreds of hours with different bullets and powder.

Sometimes the gun falls appart [weak gun], sometimes the brass fails [stronger gun].

To make useful loads for the same gun, I load up until something goes wrong, and then back off on the powder charge far enough to allow for temperature [hot chamber more than hot day], tolerance in my powder measuring, tolerance in the bullets, tolerance in brass volume, tolerance in neck thickness, tolerance in my seating, tolerance in dirty chamber, tolerance in the primers I am using, powder aging, allowance for brass life, etc. Vernon Speer put this at 6% bleow case head expansion and that is a good system.

The loads I am carrying right now are double the powder charge per SAAMI max, but I know that something goes wrong at 2.5 times the SAAMI spec.

just goes to show how foolish people are.even in the name of (testing-knowledge).

As posted earlier, SAAMI establishes maximum pressures for sporting cartridges.

While there exists software that claims to accurately estimate chamber pressures, they have empirically not been accurate.

Strain Gauge measurements are the most practical method for home reloaders to measure pressures. There is now also another alternative in Geoff Kolbe's Recoil Accelerometer (contact Clinch River Outfitters for more info). While I have a bit of experience with Strain Measurements (and can try to answer questions on this), I have none with the Accelerometer and thus can't tell you much other than the theory and equations based on such.

Hi Clark, did you every buy a barrel from Mr B?

[ 02-03-2003, 05:29: Message edited by: Chris F ]

Chris,
I have always thought there would be a future in accelerometers in guns that read an analog of pressure. The scope, given the bullet and rifle weight, could calculate velocity and pressure.

But the stiffness of mounting would be an issue in some guns, with the peaks getting averaged to look like a slower powder.

"Mr B"?
If you mean Brownell's, yes I am working on a .452/70 wildcat chamber right now in a Shilen.
If you mean Butch, no, not yet.

Hi Clark,
I believe you had contacted me for info on my experiences with barrel maker John Benjamin.

Oh, yes, It all comes back to me now.

No I never got a barrel from him. He does not advertise and I only see him when he comes up to Washington for a machinery acution.

He sent me a Spartain email:

"I make barrels from .22 rimfire to 20 mm. .22 rf and cr, 6mm, 6.5, .30,
9mm, .45, .50 bmg and 2cm.

I make match barrels for both AR and bolt rifles. They cost 200 contoured
in both stainless and 4140 chrome moly. My deliver is quite good and is not
normally more than 2 to 4 weeks.

My barrels will shoot groups under one minute of angle without exception. I
have set many national records with the barrels as well as both civilian and
military shooters.s

If you need a barrel inform me of the caliber and twist.

Regards
John"

As I may have mentioned, my barrel from Benjamin ended up costing me considerably more - even not counting the added challenges of working with him.

Chris,
When I contacted you in May about accurate barrels, my most accurate rifle was an AR-15 with 1.4" groups average with the best handload [and 50 other rifles that did 3" groups at best]. Now I have built a .257 RAI with a VZ24 action that has averaged .87" for the first 14 groups of 72 gr bullets without any load development. The barrel I used was a Lothar Walthar. It does not loose accuracy when it is too hot to hold. I think I found my barrel.