The Firing Line Forums - View Single Post - why a difference in load data between manuals

Loader9 · November 6, 2010, 12:01 AM

Wanna really get confused, go to Accurates website and look at their pdf reloading data for a 357 magnum. Now do a search(easiest way if you don't have it bookmarked) for Accurate data on the 357 Magnum in CUPs. The pdf is in PSI and the other data in CUPs you would think would be fairly close- it's not. For a Speer 140gr JHP and #5 powder, there is almost a full grain of powder difference. Other powders also show a significant difference. As most know, the 357 Mag was designed to shoot at 47,500 CUPs but the inferior guns of the day (read Smith and Wesson) couldn't stand up to the beating. The pressures have been lowered several times for this reason and the 357 Mag is just a hot 38 Special now....if you use the new data and have a newer pistol. Pressures are now 35,000 PSI.

November 6, 2010, 12:01 AM	#14
Loader9 Senior Member Join Date: July 29, 2008 Posts: 949	Wanna really get confused, go to Accurates website and look at their pdf reloading data for a 357 magnum. Now do a search(easiest way if you don't have it bookmarked) for Accurate data on the 357 Magnum in CUPs. The pdf is in PSI and the other data in CUPs you would think would be fairly close- it's not. For a Speer 140gr JHP and #5 powder, there is almost a full grain of powder difference. Other powders also show a significant difference. As most know, the 357 Mag was designed to shoot at 47,500 CUPs but the inferior guns of the day (read Smith and Wesson) couldn't stand up to the beating. The pressures have been lowered several times for this reason and the 357 Mag is just a hot 38 Special now....if you use the new data and have a newer pistol. Pressures are now 35,000 PSI.