It's probably a lemon and probably not the fault of Oly arms either. As far as I can tell the majority of the AR pistols are. Most of them are kit guns built by someone who thought they knew what they were doing just because they had assembled AR rifles before. The pistol requires a lot of help to make it work right. I was going to build one myself but gave up when I consulted with a couple people who work on them for a job. Heres a couple things I learned from the people who should know.
1. The pistol recoil buffers avaliable are too short and the springs are weak and get weaker with use. The fix for this is to replace the buffer tube with one almost as long as the one for a CAR15 model. I think you can still get them from DPMS but you have to ask them.
2. The gas port is so close to the end of the barrel that the bullet leaves before the action can cycle, and the port is either too large or too small. I think it was too large.
One of the guys I talked to said they solved some of the problems by silver soldering an expansion chamber into the gas tube.
3. The barrel being so short, the powder does not burn cleanly and fouls them up royally.
Sorry for the bad review here, hope yours works out. If they worked right they'd be very cool guns. Good Luck.
LOCHFAL