I don't know if you put this upper together or not, but whoever did worked some serious voodoo on it. This thing is an absolute hammer and leaves me with no excuses now if I shoot like crap. I was able to dial in a load really quickly switching to H4350 as I'm low on N550. I calibrated my ballistics with actual bullet drop out to 900yards on paper. My 4 shot group at 900y was 4", it held sub half-minute groups all the way from 250-900y. You guys are freaking masters. I really appreciate everything guys! My shooting buddies out here know your reputation really well and it even impressed them how quickly you turned this around. Your customer service is legendary.