I built (assembled really) a 224 based off a PSA Barrel and BCG. I used a PSA lower and all strike industries parts. I put a Luth-AR mba-1 stock and a Rifle length tube, buffer, and spring set on it. First couple shots were good. I then started to have case extraction issues. It would not extract the case after shot. I was using all factory federal ammo, as at the time Federal was the only one in the game. As of right now, the barrel and BCG are on their way back to PSA to get the issue resolved. There was a mass production of barrels that had and oversized reamer used for a large group of suppliers including some of the bigger name manufacturers of barrels. Prior to my issues at 100yrds the 75g and 90g ammo was grouping fair but not as advertised by Federal. I have been following and chasing as much information as possible on the round because I like the idea behind it 1000+yrds moa accuracy. We certainly will see. Hornady is in the game now. Different twist rates are being tested. It's not a page turner, but I think once all the bugs are worked out its going to be a good option. If your going to shoot less than 88g ammo though, just stick to a .223 and a quality barrel. The idea for this round is to launch a 88-95 g bullet 1300yrds at a flatter more stable, low recoil (2600 - 2800 fps advertised) than the big long action calibers that are more than capable of achieving that distance with the added recoil and.