I own an AR-10...unreliable POS. I'm dumping it ASAP.
I'll give you $100 for it....The AR 10 is finicky about bullet geometry. It will shoot good match grade ammo or handloaded ammo using 168 grain Sierra HPBT. Cycling reliability can be enhanced by keeping the gas rings lubed. I found this out the hard way. Once those rings are worn, the damn thing will lock open on every shot. Shooting it with dry gas rings will screw it up after 300 rounds or so.
I miss my AR-10. Since I refused to register a rifle in Kalifornia that I already owned, my rifle has been residing out-of-state for some time now.
When I first purchased it, I had reliability problems.
The first problem was a failure to properly eject. The expended brass would get caught by the bolt and prevent proper feed of the next round. I puzzled over this quite a bit, finally taking measurements of clearances. Much to my surprise I discovered that the manufacturer had mis-assembled my rifle and installed an AR-15 buffer which is longer than that for the AR-10. The proper part allowed the bolt to retract about a half inch farther and the ejection problems were over.
I then discovered that there was a problem with chambering some ammo. Examination of the rounds that failed to chamber revealed that they were getting caught on a slight ledge where the barrel mated with the feed ramp. A local gunsmith polished this area for me. Since that time I had no reliability problems whatever. It's a fun rifle to shoot.
When my Springfield Armory M1A arrived (the replacement for my AR-10) I had feed problems with it. My success in trouble-shooting the AR-10 made me confident that I could find the problem. The problem turned out to be that the hole which directs gas from the barrel to drive the ejection apparently had a burr in it, preventing sufficient ejection force. A couple of small drill bits cleared the hole and the rifle now works fine.
If the manufacturer hasn't been able to make the rifle work, then I recommend that you find someone to go shooting with you who is comfortable with how the rifle works and who can experiment with it to find the problem.
My thought exactly when I saw this article. If I could trade my AR-10 for a reliable .308 Bushmaster clone I would do so in a heartbeat. Mine has been sitting in a safe for the last four years. I got tired of clearing failure to ejects and trying all the innovations that Armalite claims will solve the problem. When you pay $1500 dollars for a rifle and about $60 per mag (which you have to modify yourself) you expect not to be embarressed at the range sitting next to guy shooting a knock off gun that fires all day long.