Mostly I use a .411 diameter 400 gr Barnes TSX from a run they did a while back and it’s a great bullet. The other bullet I’ve used is a 400 gr North Fork cup point solid which if you are just shooting buffalo is great. I like to load a solid under one or two TSXs but I find managing two different loads to be a pain, with the cup point it’s the only bullet I use. It’s not as good for distance and you have to be careful in herds as it will shoot through a broadside bull. The Swift A-Frame is a .410 which probably does not make difference but the cannelure is in the wrong place for a crimp on my rifle.