I prefer the 370 gr maxiball. I have only used Pyrodex RS. I'm sure P and Select will also work fine with certain loads. I use 10.75 size caps made by a company called Dynamit-Nobel RWS (as I recall, not positive though). I have not found hotter caps, judging from the sound of a variety of caps fired alone. They fit tight on the nipple. I actually (carefully) compress them on with the hammer, and have to remove them with a knife or key, whatever is handy.