My Winchester M92 in .357 Magnum loved fast bullets and not slow ones. Super Vel 110 grain ammo made it shoot like a target rifle - one ragged 5 shot group out to 50 yards. As the bullets grew in weight and slowed down, group size grew.
Super Vel .38 ammo was OK at 110 and 125 grains, but always key holed at weights of 158 grains and above.
This was years ago before I knew about twist and such, so I just bought and/or hand loaded bullets that approached or exceeded 2000 fps and all was well. I had some real smoking 125 and 140 grain loads that shot flat and were accurate.
I hope this helps to figure out your issues.
