Friend recently got one. The handgaurd and barrel nut came loose first time he took it out. Brought it to the shop and the barrel nut just needed to be shimed. No big deal that's normal for rails that require timing, just some idiot who built it was too lazy and thought 20ft/lbs was good enough I guess. Then I discovered a real problem, the front of the upper receiver is so out of wack the barrel actually points to the left. Needs lapping to true it up but I don't have a upper lapping tool yet. I've heard of it but this is actually the first time I've seen the need for one.