Pudge
Member
Is there a formula for this? Is the pressure measured for each load? I have 2 manuals and check out the web page for the powders I use, and there is not consensus. My Speer book from 1986 is usually much more agressive, and considers anything under18,500 cup to be standard pressure for .38 special and I think 22,500 cup to be the upper +p limit. My Lyman 49th edition I don't think exceeds 18,700 C.U.P. for +p. BUT there are some standard pressure .38 special loads that exceed the top +p load that the Speer book lists. And the web page is even more conservative with the pressures.
How is this stuff measured? How significant is bullet weight in its impact on pressure? My Lyman manual lists as standard pressure max loads for 155, 158, and 160 grain cast bullets as 4.7, 4.0, and 4.9 grains of W231 respectively. Why would the 158 grain load be so much lighter? Should I weigh the slug dry, or lubed? What about a gas check design, does it change max load if used or not?
I'm asking because the 4.8 grains of W231 behind a Lee 90322 (which is advertised as 158 but weighs in at 160+) is very accurate our of my revolvers, but one of them is a Colt Cobra, is that too stiff a load for practice, or should it be ok in the aluminum framed revolver? Or should I use lighter less accurate loads as a precaution? Or is there a formula I can use to determine how much pressure I'm creating, and if so, is there a reasonable guide for use for alloy framed revolvers?
How is this stuff measured? How significant is bullet weight in its impact on pressure? My Lyman manual lists as standard pressure max loads for 155, 158, and 160 grain cast bullets as 4.7, 4.0, and 4.9 grains of W231 respectively. Why would the 158 grain load be so much lighter? Should I weigh the slug dry, or lubed? What about a gas check design, does it change max load if used or not?
I'm asking because the 4.8 grains of W231 behind a Lee 90322 (which is advertised as 158 but weighs in at 160+) is very accurate our of my revolvers, but one of them is a Colt Cobra, is that too stiff a load for practice, or should it be ok in the aluminum framed revolver? Or should I use lighter less accurate loads as a precaution? Or is there a formula I can use to determine how much pressure I'm creating, and if so, is there a reasonable guide for use for alloy framed revolvers?