GunnyE7

I have been loading .357 magnums for my blackhawk 10.4 grs of 2400 with a 158 gr cast swc great performer.+ or -1140 fps good accuracy.When I load them in my Rossi(20in carbine) the accuracy is all over the place even at 50 yds I have shot 158gr jhp with the same load
and have good accuracy.do I need to jack up the load for the cast bullets to get them to settle in and what about leading with the higher velocity

d80hunter

I load 12.5 grains of 2400 with a 180 grain XTP. I get about 1500 fps out of a carbine. I call tell a big difference between my load and factory 158 grain ammo when shooting deer. I shot this load out of my revolver too.

If I wasn't using them in a revolver I would load 15 grains of Lil'Gun and get another 100 fps out of the carbine.

Finepoint

I've owned a couple of Rossi M-92 clones in this caliber over the years. The older ones(>20 yrs) clearly did not like lead bullets or weights over 158 grains. A current production one I have does well with 130-158 gr hard cast bullets up to 1200 FPS, then loses it's grouping. It still doubled its group size going from 158 to 180 grain with jacketed bullets, so lighter jacketed bullets are in order.
Interestingly, my Taurus M-92 clone in 357 does just fine with a full load of H-110 and a 180 gr Hornady HP or Nosler partition, shooting 1 1/2 groups at 50 yds. Velocity averaged 1510 fps from a 16" barrel. Since Taurus now owns Rossi, it suggests that Taurus uses different barrels, at least in the stainless models.

Hummer70

If you have someone with a bore scope get a looksee down barrel. It may be leading up on you.

I had a Marlin 357 and shot Sierra 158 gr JSP with 2400 and it would print 6" at 200 yards.