Yes, thank you!It appears to be what is called a "semi-wadcutter" bullet. This is a type of target shooters' bullet flat enough to cut a visible hole in a paper target, but still round enough to function in a semi-automatic pistol. 12 grams is pretty close to 185 grains, which is one of the standard weights for .45 ACP bullets. If that's what it is, it should measure around .450 - .452 " in diameter.