Not sure ya need TWO INCH accuracy as a spec, particularly in a high-stress, perp-in-motion, self-defense shooting scenario.
If I am hitting roughly center mass, particularly upper torso, with 6 - 12” (picnic plate outlines on the Barney Fife target) 3-round quick-fire groups, at 12 - 15 feet, I am happy with that, and pretty certain the .45 rounds WILL stop the threat.
Two inches is what I train to perform. Don’t always get it but I can hit in regularly on the range in no stress and about 50/50 on speed drills. I stress 2” because most people under stress will increase that radius 2x or even 3x. I figure 6” in close quarters battle will be good enough to hit the heart or head.