.308 is what you want. Recipes for 7.5x55 are in the major handbooks. Your 1911 doesn't have fully supported case-head like the K31, though, which makes hot loads dangerous. Stay on the lower end of things and make sure you don't overcharge a case and you'll be fine.

.308 is what you want. Recipes for 7.5x55 are in the major handbooks. Your 1911 doesn't have fully sppurted case-head like the K31, though, which makes hot loads dangerous. Stay on the lower end of things and make sure you don't overcharge a case and you'll be fine.