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Old August 21, 2012, 09:35 PM   #1
GI Sandv
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Join Date: December 16, 2008
Location: Minnesota
Posts: 65
Stuck Bolt Carrier Group

I just bought a fully assembled upper from a guy who builds guns locally. I bought one with a nickel boron bcg thinking that I wouldn't run into too many issues with cleaning, dirty loads, etc. Lo and behold, I loaded my first mag with three rounds to zero the gun in and, "click." Failure to fire. I attempted to eject the round but the charging handle would only pull back about 1/4 inch. I dropped the mag, attempted the charging handle and again no luck. I tried using the forward assist to no avail as well. After attempting this a few times I called another guy at the range over and we pulled from two ends of the gun, me from the barrel and him from the charging handle. This finally worked. The primer had a scuff mark where the firing pin had hit but it wasn't even a full depth dent. I loaded the round back into the mag with a different round on top this time. I released the charging handle, selected fire, and "bang." It fired all three rounds this time, including the one that had failed to fire previously.

Unfortunately, this happened a few more times. If I remember correctly, each time it happened was from me pulling the charging handle all the way back and releasing, rather than locking it back and hitting the bolt release. Eventually I just pulled the upper off, tried to pull the bolt as far back as it would go (1/8 - 1/4 inch) in order to avoid accidentally hitting the firing pin, and I would pry the bolt back with a flat head screwdriver. Sometimes it was more stuck than others. But in every case I either had to pry the bcg loose or have another person help me pull the charging handle while I pulled on the barrel. (Don't worry, the barrel was still pointing down range and not at any of my body parts.)

Eventually I took the bcg apart and was able to easily wipe away any and all fouling from the few rounds I'd already fired. However, on the back side of the bolt (not the bcg), on the rounded/sloped part just behind the two c-rings where there's often a good amount of caked carbon on well used bolts, there was a solid deposit of fouling and copper. I was surprised because all of the rest of the bolt wiped clean with a rag, just as advertised with these nickel boron carriers and bolts. I didn't have the appropriate tools to clean this off so I left it, but wiped it with some CLP and ran a rag over it, which only took off a little bit of it. I'm not sure whether this would be resulting in the carrier and rounds being jammed in the chamber or not. The only other things that come to mind are that the extractor pin is pushing too hard against the round, creating extra perpendicular pressure against the chamber, or that my brand new p-mags are pushing on the carrier in a strange way. But removing the mags doesn't change anything. I'm not sure whether it could be the bolt itself or not, since I don't have this problem unless there's a round in the chamber. Could it just be part of the breaking in process? I only put about 40 rounds through it today and for what it's worth, I was using American Eagle 55gr FMJ rounds.

Any thoughts would be greatly appreciated. I plan to go back to the range tomorrow and see what I can figure out. After that, I'm calling the guy who built the upper.
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