Magnumite
Ultimate Member
My experience is the gun gets beat up trying to get much beyond that velocity range.
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Todays test was 13.5, 14,& 14.5 of 2400 with the Sierra 158 jhp. Same results, high SD (40), and maxed out at 1300 fps more or less. The SD is so bad, it's really hard to see a difference in velocity in the averages.
However, with the 44 mag using 2400, starting at 19 and working up in half grain increments the powder was predictable. 21 grains got me 1391 fps average. Using a different lot of powder (friends), 21 grains was 1450. So in that gun, with my lot, I'm going to try 22 grains.
I might try 15.5 in the 357 mag, but I noticed today the cylinder has a good bit of back and forth play. I really think im venting too much gas because of cylinder gap and I'm just going to be at this 1300 to 1350 fps limit.
How do your velocities look with factory loads ? Do you have access to other .357 revolvers ? Maybe your gun is " slow " .
be sure to remember you have to meet or exceed the 700 foot pounds with the new rifle pistol law. a 158 grain bullet of any kind in a 357 magnum is not going to exceed the 700 foot pounds in a short barrel handgun. if i am wrong please tell me how you can do it with a 158 grain bullet.
a 158 grain bullet of any kind in a 357 magnum is not going to exceed the 700 foot pounds in a short barrel handgun.