I have never used them in a rifle, but I have been "attacked" by a lot of rattlesnakes, and forced to defend myself with a 4" .357 loaded with CCI shotshells. Usually at a range of four-five feet, sometimes they would almost take the snake's head off, other times I would see dimples appear, then disappear, on the top of the head, and old mister snake continued his attack. My follow-up round of Remington 125 gr HP never failed to do the trick. So do not rely too much on shot shells, at least in .38/.357. I can't say about .44's, I sold my Model 29 (sniff sniff) before I ever got a chance to try them...