A coworker bought a AR-10. He's not a gun guy but is diving in head first now like many others. He took it to the range the other day and told me he had problems with it. After decifering his non gun language i found out it was not extracting the case from the chamber and trying to load a new round causing it to jam. This causes a bigger problem with fixed mag guns to clear. First i asked if he cleaned it when he bought it and he said no(didn't know he should) so i figured this might be the problem. Later that day i thought about it some more and asked what kind of ammo he was using and he mentioned several types one of which was steel case junk ammo which he used first. So i figured maybe he chambered was gummed up and told him to bring it over and i would clean it and show him how too. He did that last night but i didn't see anything unusual but cleaned it and told him to come to the range today. I also looked at the extractor and checked the spring which seem to look and work normal. Today every single round he fired would leave the case in the chamber but you could manually extract it after you closed the bolt again. It's a black rain ordinance rifle and i told him to google them while we were at the range and call them right now. He did but the tech guy wasn't there and he has to call back Monday. He's a bit frustrated after dropping almost 2k. What are others opinions as to what might be happening. besides a dirty chamber, bad extractor or maybe a chamber burr what else could be causing this? Hopefully the company will have him send it back or be able to tell him what the problem is over the phone.