Had a student in my recent Combat Carbine Teamwork class who was having issues with his AR’s, mostly related to failures to extract and eject. I had him leave it with me so that I could go through and correct any issues I might find.
Gun is an Anderson lower and an unknown, assembled, complete upper.
I didn’t fine a single culprit, but did find numerous small things that could cause issues when added up.
A thorough cleaning of the upper receiver assembly and BCG, especially the barrel extension and chamber.
Replaced the extractor spring and insert with a set from Sprinco.
Replaced the ejector, ejector spring, and pin.
When I pulled the rail, I found a lot of gas debris all over the barrel behind the gas block, as well as inside the handguard, due to a gas block with a loose fit to the barrel. Other than that, the barrel was dimpled and the block lined up appropriately. I replaced the gas block and gas tube.
While I was in there, I pulled the barrel nut, which seemed to be overtorqued. I shimmed the barrel nut so that it lined properly without having to overtorque it. Barrel nut was installed properly, along with the new gas block/tube, and the old flash suppressor with a new crush washer.
Found the buffer to be lighter than ideal for a 16” barrel with a carbine gas carbine, at 2.8oz. I replaced the entire buffer system with a Vltor A5 7-position receiver extension, a Vltor A5H2 buffer, and a Sprinco “green” rifle spring. Replaced the castle nut, and installed a Griffin Armament receiver end plate with anti-rotation QD socket. Staked the newcastle nut twice.
I’ll get to the range ASAP to see if the issues are corrected.
Gun is an Anderson lower and an unknown, assembled, complete upper.
I didn’t fine a single culprit, but did find numerous small things that could cause issues when added up.
A thorough cleaning of the upper receiver assembly and BCG, especially the barrel extension and chamber.
Replaced the extractor spring and insert with a set from Sprinco.
Replaced the ejector, ejector spring, and pin.
When I pulled the rail, I found a lot of gas debris all over the barrel behind the gas block, as well as inside the handguard, due to a gas block with a loose fit to the barrel. Other than that, the barrel was dimpled and the block lined up appropriately. I replaced the gas block and gas tube.
While I was in there, I pulled the barrel nut, which seemed to be overtorqued. I shimmed the barrel nut so that it lined properly without having to overtorque it. Barrel nut was installed properly, along with the new gas block/tube, and the old flash suppressor with a new crush washer.
Found the buffer to be lighter than ideal for a 16” barrel with a carbine gas carbine, at 2.8oz. I replaced the entire buffer system with a Vltor A5 7-position receiver extension, a Vltor A5H2 buffer, and a Sprinco “green” rifle spring. Replaced the castle nut, and installed a Griffin Armament receiver end plate with anti-rotation QD socket. Staked the newcastle nut twice.
I’ll get to the range ASAP to see if the issues are corrected.
