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Posted: 2/22/2010 8:43:00 PM EDT
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Hey all, just took my new build to the range this past saturday. First full magazine went through without a hitch, then after that, the bolt would not go into battery all the way and won't chamber the round fully in. forward assist knob would not work because it wasn't forward enough to catch. Would do this every other round. Ended the day with about 120 rds through her.
Did the short stroking test and passed. Not sure if it might have something to do with the gas tube and gas key alignment because when I drop the bcg into the upper on its own wait, it doesn't seat in all the way, I'd have to push the last .25 inches in. Setup: Del-Ton 16 inch upper with hbar and chrome lined barrel. Standard Del-ton bcg Del-ton lower parts kit on JD lower with commercial buffer tube. Using brand new Magpul pmags. PMC bronze .223 Here are some pics for reference. http://picture.vzw.com/mi/498158536_1750962892_0.jpeg?limitsize=580,480&outquality=56&ext=.jpg&border=1,0,0,0 http://picture.vzw.com/mi/498158525_1750962855_0.jpeg?limitsize=345,345&outquality=56&ext=.jpg&border=2,0,0,0 http://picture.vzw.com/mi/498158520_1750962829_0.jpeg?limitsize=345,345&outquality=56&ext=.jpg&border=2,0,0,0 |
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If you want to check gas tube and carrier key alignment, remove the charging handle and bolt and try running the bare carrier into the upper receiver. If there is any interference between the gas tube and carrier key, it will be obvious.
Was your new build clean (especially the chamber) and well lubed? Sometimes new rifles need a little use to loosen up. The bolt lugs need to wear in a bit and the carrier rails will need to mate to the upper. |
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It was clean and lubed generously with slip 2000. I did the bcg test by letting it slide into the upper receiver on its own weight with the CH removed. It would slide in on its own all the till about .20 inches left and I would have push the rest of it in to battery, not with a lot of force but just a little bit.
Is the gas tube and gas key suppose to mate up real snug? or is it suppose to be kinda loose? Read some other threads describing how to tell worn out gas tubes, so I'm guessing its supposed to be pretty snug. I also forgot to mention, for a new rifle, is there suppose to be a lot of brass debris on the bolt and bc and in the chamber? |
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This is my first AR, I've only had AK's before this. I don't understand why AR's are so picky with different ammunition. I can understand steel cased stuff, but I mean brass cased stuff is pretty pricey, even when it comes to the low end brass like PMC that i'm running.
How would one go about building an AR that could run any brand of ammunition? (excluding steel cased stuff of course) |
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Carrier alone without the bolt,
Drop the carrier into the upper and let it slide forward/downward until it touches the barrel extension. If you have to force the carrier down to get it to seat against the barrel extension, then take a good look at the alignment of the key to the gas tube. IF needed, tweak the gas tube above the barrel with the hand guards removed to correct the alignment. Also, you should be able to wiggle the gas tube in the upper receiver (in the upper tube channel of the receiver). If the tube is rock solid, then when the barrel nut was tightened, it was not correctly indexed to align with the upper feceiver tube channel, and now have the tube forced to one side of the upper through channel (read a bad thing and will not allow the give in the tube to self align). If this is the case, the the barrel nut index will need to be correct, hence if not done, one side of the tube is going to prematurely wear out quickly. |
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