No Hope For Me
I'm also glad to hear you figured it out.
Citizen, Patriot, Ranger
Glad to hear that you got it worked out. I have run into the same issue w/ Model1 Sales. In one case, I had to throat and finish ream the chamber in order to get a round to seat fully. For future reference, the green scotch pad method is the least invasive way to clean up a chamber. I takes very little away in terms of actual metal. If you followed the tecchnique you described, you should be fine! I use an in and out technique to create a swirl pattern inside the chamber, kind of like polishing brake slave cylinders or V8 cylinders.
One thing to always remember: Never mess with the gas port size! A burr in the bore can ruin your whole day! Not to mention the really heavy recoil if you overbore it! Accuracy tends to suffer a lot under these circumstances.
I wasn't about to enlarge the gas port, the brl isn't that short. I'm glad you guys mentioned polishing the bore, the only thing I could think of was headspace. I knew the problem was in the chamber and not with the ejector or anything else. I just didn't know what was wrong with the chamber. I figured someone here would know! Thank you guys for the help!
I've had the same exact experience with a DPMS upper I bought several years ago. It wouldn't eject the empty casings all the time and the brass was showing signs of a gouged chamber. It would've been impossible to full length resize. Must've had a chip or burr when maching the chamber or possibly not enough coolant? I purchased the upper new/complete from a vendor at a local gunshow. He said he'd take it back to his shop and polish it up. The brass bulges were so deep, I told him I felt it was a manufacturing defect and wanted the barrel replaced. It was sent back to DPMS and was replaced with a new upper n/c.
Ahhh! The sweet sensation of success!
Originally Posted by moleman
Yep, I was pissed this weekend when my AR stopped working! I am not sure what's wrong. It might be ammo. I was using Wolf, which I hear is crap. It also might be that I didn't run the rifle wet (or wet enough).
It would go bang and not extract the round, it would be jammed half extracted. I think it's the ammo because the week before it would cycle but jammed on feeding frangible ammo (wouldn't pick it up). Prior to that, I cycled 200 rounds with no failures to feed or extract. Ammo was different all three times, this is a DPMS CMP with the HBAR barrel.
Any ideas? I think it's picky about ammo. I couldn't find any problems while cleaning it.
I'm no expert, but my shootin' buddys rifle was doing the same thing and his gas block was mis-aligned with the barrel gas port. After we re-aligned the gas port it cycled flawlessly no matter what type ammo we shot.
Easy and cheap fix.