My current choice for a .50 cal conical is the Hornady FPB, which has a BC of .285, which ain't bad.
Actually, BC isn't an issue for me as I still regard MLs as short-range propositions. I know that they can reach out there a bit, but it's not what I'm looking to do.
I'm not being critical of .45s at all. If the gun I wanted had been available in .45, it would have been considered, but again for my use, the .50 was a better choice.
