My SHTF zombie apocalypse gun is an XD. And I generally buy whatever .45 ACP is on sale. I've never really paid too much attention to bullet grains, as I don't spend much time shooting for distance, since there aren't many 1000 meter ranges around me. I've run 185 and 230 grain rounds through the XD, and notice no difference in accuracy, recoil, etc. I know what the .45 is capable of, and more importantly, not capable of. But I know I'm missing something here. What's the difference?