Greetings. I'm new to the AR-10 and have a very basic question. I've just received an upper from Midway (AR Stoner) with side charging handle. I just put it on my lower and the bolt is sticking/catching when pulling back. I've never had this issue with any of my AR-15s and wondered if this was just sloppy machining that will fix itself and loosen up after a few rounds or if there is something else I'm missing. (Yes, I know I should have done a higher-end upper, but this was all I could currently find in stock)
