I understand what you are saying MM, but I believe the 5.56 will put someone down a lot more decisively at close range, than a 9mm or similar. It will also defeat most body armor. That's probably why entry teams are using the 10.5" and similar ARs.
I think the 10.5" has advantages over a 14.7" in close quarters, tactical stacks, fighting from inside vehicles, etc. I'm not doing that type of shooting.
I had to have a 10.5 due to the fact PSA nearly gives the uppers away....grin. For me it's a cool play toy more than anything else.
I do have 10.5 and 14.7 ARs, I prefer the 14.7" by a good margin for the type of shooting I generally do. For a home defense, I'd grab the 14.7 every time.
