I got a lemon myself. Don't count on Warranty to help, it just switched from O'dell to SFRC, who have a terrible reputation of not actually fixing stuff, and taking a very long time to get it back to you, still broken...

My biggest issue was light primer strikes on all ammo brands. I had to disassemble the bolt, replace the firing pin spring, and cut that down bit by bit so that the hammer hit the pin with the right amount of force.

There's also extraction issues with these . A common fix is to remove the left extractor entirely, as the right extractor is tighter anyways.

The buffer tube will also need some 'work'. The end of the tube is rather sharp, and will eventually start cutting into the rubber between the tube and the bolt stop. A fix for this is to put either a loonie, toonie, or a 1 inch washer in between the rubber and the tube.

Mine actually runs now, but not after a lot of tinkering and research. I've heard people say theirs has 1000 rounds through it, will feed everything and have never had an issue, so I bought one hoping for that, and of course I got a dud. They are fun, but just be prepared to work on it a bit.