The reason I was asking about the twist rate is that I have a bunch of 405gr and 355gr BTB that I bought for my Blackhawk 45LC and was curious if they would stabilize in the slow twist of the Rossi.
Well I got my answer yesterday. Yes!
Much to my surprise the heavier the bullet, the tighter the grouping at 50yds. And no sign of keyholing what so ever. I'm thinking that I may just have to go get a tang site with aperture front site and see about doing some shooting out to 150-200yds.
And just my luck, all bullet weights from 300gr -405gr had almost the same point of impact. That just happened to be at the very bottom of the vertical adjustment. The 300gr being dead on and the 355gr and 405gr being about 2" low. The only problem I did have was with Some 240gr JHP, they were about 8" high.