I said past 80 yards in multiple posts based on your numbers for expansion, and after that no better than a 5.7. I also said based on that it would probably work fine inside a house, in my opinion, with the accompanying blast. I also said the 300 blk with rounds like the TSX give you a much larger window. And, in my opinion, would make a much better round out of short barrels. SBRs are already a compromise, I don’t want to give up even more when I don’t have to.
I’m pretty sure most defensive gun use is within hand gun range, but there are exceptions (Walmart has pretty big parking lots). If I was going to go through the trouble of carting around a rifle, I want a rifle.
Now a little brief case with an MP5k tucked inside would be neat.
I think some people might be taking this personal.