Thread: Chamber pressure, expansion ratios and muzzle pressure

Originally Posted by gundoc

I would put the first step down at 8 inches and the second step at 12 inches from the breech, with both steps being radiused to remove stress points. You should bore the barrel to be only a 1mm wall at the muzzle. The major diameter should leave about a 2.5mm wall at the narrowest part of the barrel shank (ie: the bottom of the threads). Tricky work but quite do-able.

Yes looking at that pressure curve it's 50% @ 10" and 25% @ 20"
So consulting my proof house data and looking at the same bullet diameter in lower pressure cartridges I can calculate the minimum barrel wall thicknesses
It will work just fine

And the bore drills are easy.
I might be able to use some of my existing ones and just grind them to take a live pilot if the existing fixed pilot is too small