Originally Posted By: gjw
Hey Mike, well when your gun is proofed at 8938psi and you shoot 2 3/4" in a 2 1/2" chamber, then yes, 7000 is better than 9000

I should have stated that I was speaking of vintage Brit guns.

Sorry for any confusion.

Best,

Greg


There's the answer right there--except I'll make one friendly amendment if you'll permit, Greg: I'm pretty sure that 8938 psi number is service pressure and not proof pressure.

But a reloading recipe that lists 7,000 psi can, all of a sudden, get awfully close to 9,000 psi if it's a 2 3/4" hull used in a gun with short chambers (which, per Sherman Bell's tests, can potentially add an additional 1,000 psi + to the pressure reading). Then add in a bit more in case your powder drop is a couple tenths of a grain higher than average.

I don't see any need to seek out the ultra-low pressure stuff. Under 6,000 psi, for example. But if you're reloading 2 3/4" hulls for short chambered guns, you do want to build in a significant safety cushion. Somewhere around 2,000 psi should be sufficient. Nothing wrong with more than that, but it's not really necessary in terms of safety.