I've done research over the years about this, in preparation for this, but I see so much conflicting information. I am finally about to put together an AR pistol but I really can't decide, based off of forums and even velocity data, wether or not it's smart to go with 5.56. The plan has always been an 8" 300 AAC, but I will have to build up ammo stock to shoot that and I can have fun with a 5.56 right away. The problem with the 5.56 is that supposedly it will be JUST a toy. I want something that looks aesthetically pleasing, like a toy, but I also want it to be useful, if ever I would need it. And forgive my foil, but I am not talking about home defense, as I already have so many other options for that, but SHTF. I read that an 8" 5.56 is stupid for things like that, so I was considering a 10.5", but I read that THAT is even insufficient, as the round was design to burn in at least 12" of barrel. Supposedly there are damn near no cons to having an 8" 300. My only reason for this is that it's even more costly to get into that game, otherwise I'd buy a few thousand rounds and not make this thread. So am I missing anything? Would you all trust your lives to an 8-10.5" 5.56 AR, or would it be stupid not to start getting into the 300 AAC game, since I have that opportunity right now? I appreciate any and all advice, ridicule, and information. God bless and hope you all had a WONDERFUL Thanksgiving.