load pressure

mustang071965 · March 16, 2006, 03:38 PM

i have been reloading for my sharps 45-70 for about a year and a half. i cast my own bullets, 535grn layman postel. 20-1 lead. i use rem primers large, rem brass. i reload using the 48th edition laymon book for this load. im am using rx7 37grns. in the book it shows aroung 1300 feet per sec. with a pressure of about 14000. i just bought a conograph and tested the load. it averaged 1500 feet per sec, with a standered div of 8.12 feet. at 150 yard with iron sights it grouped under 1 inch. my question to you or any member is there a pressure increase sence i have 2 more inches of barrel then the test barrel from laymon, or does the pressure stay the same and only the speed increase with the 2 extra inches of barrel.

Art Eatman · March 16, 2006, 05:09 PM

The pressure is not increased by a longer barrel. The force due to the gases is applied to the bullet for a longer period of time.

Art

mustang071965 · March 17, 2006, 01:23 PM

thank you Art. i just wanted to be sure. i thought the pressure stayed the same since no increase in powder, and that the speed would increase with extra barrel lenth. this is a very accurate load in my sharps. the only proublem is finding some thing big to stop it. mustang071965

March 16, 2006, 03:38 PM	#1
mustang071965 Junior Member Join Date: March 16, 2006 Posts: 3	load pressure i have been reloading for my sharps 45-70 for about a year and a half. i cast my own bullets, 535grn layman postel. 20-1 lead. i use rem primers large, rem brass. i reload using the 48th edition laymon book for this load. im am using rx7 37grns. in the book it shows aroung 1300 feet per sec. with a pressure of about 14000. i just bought a conograph and tested the load. it averaged 1500 feet per sec, with a standered div of 8.12 feet. at 150 yard with iron sights it grouped under 1 inch. my question to you or any member is there a pressure increase sence i have 2 more inches of barrel then the test barrel from laymon, or does the pressure stay the same and only the speed increase with the 2 extra inches of barrel.

March 16, 2006, 05:09 PM	#2
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	The pressure is not increased by a longer barrel. The force due to the gases is applied to the bullet for a longer period of time. Art

March 17, 2006, 01:23 PM	#3
mustang071965 Junior Member Join Date: March 16, 2006 Posts: 3	thank you Art. i just wanted to be sure. i thought the pressure stayed the same since no increase in powder, and that the speed would increase with extra barrel lenth. this is a very accurate load in my sharps. the only proublem is finding some thing big to stop it. mustang071965