That's good to know, I've been having a hard time deciding between a 7", 8.5" and 10.5" and only have found a little bit of info on how the guns run using those shorter gas systems. What I did come across was some info on shorter barrels being potentially harder on the buffer and may cause premature wear - something to keep an eye on I guess. I did a little 'shopping' last night and found 2 uppers on Hardened Arms in the price range I'm looking for, but not quite the setup I wanted (I don't want a full quad rail up front). I also checked out Primary Arms, Palmetto and one other I can't recall at the moment. All of them had 10.5" pistol uppers in the $200-$250 range (no BCG/CH), but I wasn't quite happy with any of them. I'm in no rush on this so I'll keep looking around and keep coming back to Hardened to see if they add anything else. In the end, I may just buy the cheaper quad rail model and buy my own forend/guard to make what I want. I was also curious about some different flash hiders that might help reduce flash back toward me, especially for home defense. More research. I did end up taking step 1 on an AR9 build though and put in an order for a stripped AR9 receiver from Palmetto. Not sure if that will be a pistol or carbine yet, need to think about that some more.