I have been unable to find much info on this topic. I'm trying to work up some loads for a 3" .357 mag, but all the data is for 6 and 7" barrels. I'd like a nice potent round with 180 grain hard-cast bullets to pack while bowhunting. Most of the data I have says H-110 is the best powder, but I'm wondering if it's too slow-burning for such a short barrel. Has anyone chrono'ed some loads out of a 3" gun? I'm thinking something like HS-6, HS-7 or 2400 may be a better choice.