Just curious. I have a 10.5" pistol. Fun, but if one was looking for something that felt like an SBR (as in significantly smaller), it's not a huge difference. But what's nice is once you've got the lower squared away, you can always swap out and try other uppers. My current favorite AR is my 8.5" blackout pistol.I've always heard good things about Geissele actually. I think my bro might have one in his AR and he likes it. But I have no experience with them (I might've shot his AR once with it in, can't remember).
Yeah, there is the State lines advantage to the pistol route. I'm not too worried about that though. It would be a rare case for me to do that; the only reason being that I'd be taking it to an out-of-state training class which case I'd maybe just take the 300 BLK pistol if it was going to be a problem with the SBR.
No particular reason for the upper I was looking at. I think around a 10.5" - 11" would be ideal for me. I think I heard John Lovell of Warrior Poet Society said something like that, or he enjoys that length, and I figure the guy knows a thing or two about shooting. Plus at 10.5" - 11" range you don't lose a ton of the potential speed/power of the 223/556 round. You can definitely shoot out to hundreds of yards at that barrel length and make hits.