I put together an AR pistol in .300 BLK, using a 8.5 inch PSA upper. Function' fit and finish all see fine. I am sighting it in using just basic iron sights and that is what I plan to keep on it. At 50 yards it hits about a foot right. I have to adjust the rear sight almost all the way to the left for it to hit where I aim. That being said it is very accurate.

It is kind of odd looking, but I don't necessarily mind it. My question is what could be causing this? I'm shooting 200 grain ammo...which I figure might throw it off some but not that much. I'm guessing it could be a lot of issues, barrel bored slightly off, rail or sights off enough to matter but not enough to see visibly? I'm not sure. Would there anything be wrong that can cause damage or looseness later?

I wasn't sure exactly where to post this since it is technically a pistol but is used like a rifle.