Shotshell Pressure Question?

Drew Hause · 09-20-2010, 01:01 PM

Mike: Tom Armbrust tried to pressure test some vintage loads a few years ago. The results (probably more primer deterioration than powder) were so inconsistent as to be meaningless. He did find a trend toward increased pressure, felt to be from hardening of the old fiber wads and paper cases.

In a 1927 Western Cartridge Co. flyer "Super-X The Long Range Load" by Capt. Chas. Askins, the 12 gauge duck load is described as 38 1/2 grains or 3 1/2 dram with a muzzle velocity of 1400 fps (modern numbers are measured 3 feet from the muzzle) and a breech pressure of 3 3/4 tons or just below the current SAAMI 12g maximum of 11,500 psi.

Austin W Hogan · 09-20-2010, 07:23 PM

Speeds were measured with what is known as a ballistic pendulum. The shot was fired into a bullet trap on the bottom of a pendulum. The speed was deduced from the amount the pendulum rose.
I wish I had my old freshman physics textbook; it had a picture of a ballistic pendulum, and the math outline. It was a really good excercise to convert the potential energy of the pendulum back the the kinetic energy of the projectile, and then the speed of the projectile.

Best, Austin

Mike Stahle · 09-20-2010, 08:00 PM

Thanks Austin,

Very cool info. I learned something today

Autumn Daze · 09-20-2010, 08:47 PM

Check this out....guy's

http://www.google.com/url?sa=t&sourc...p5BgO6SGhyH_mA

Mike Stahle · 09-22-2010, 07:21 PM

Quote:

Originally Posted by Dave Suponski

Check this out....guy's

http://www.google.com/url?sa=t&sourc...p5BgO6SGhyH_mA

Thanks Dave, very interesting

Mike Stahle · 09-22-2010, 07:54 PM

This will be my next pressure test load. This will be my tree-rat load if my baby and I survive.

BTW: I never did hear back from Federal, so much for the "we will reply within two to three days"

Bruce Day · 09-23-2010, 07:41 AM

Quote:

Originally Posted by Mike Stahle

This will be my next pressure test load. This will be my tree-rat load if my baby and I survive.

1. Write if you survive.

2. There is no turning back once you start living life on the edge.

3. Join the PGCA.

4. By the way, I've shoot cases of those in Damascus and fluid steel guns for hunting. In 12ga 1 1/8oz, in 6's that is my standard pheasant and prairie grouse load except for 16ga and then I buy the Fed 1oz for that.