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Posted: 1/30/2011 3:35:26 PM EDT
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This is my Del-ton upper/American Tac. lower I built not too long ago. The bolt is either slipping off the case or not catching all the way or something and jams the round between the bolt and the feel ramp. It doesn't have M4 ramps and I can't remember where I got my bolt from. Any thoughts?
https://doc-00-30-docs.googleusercontent.com/docs/secure/b7vu9b2hc2cg2geebj7cjjk7sr1c0rqt/bjhpl9mcn8g4qh55mmj0kgumc3b6kqvr/1296432000000/04766790905415008176/04766790905415008176/0Bx42xcfFd-7cODYwZTc1YjYtYTg0Ni00OTk4LWEzNjctM2IxM2U1ZGFiNDVh?nonce=tfeidn62l3bio&user=04766790905415008176&hash=9v8epcviovvql9sqphsc0ugb0c472rrt |
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You have an extraction problem going on that is causing short stroking, and chance are the way that you are cleaning and lubing the rifle is coming back to bite you in the ass.
Sweets to clean the copper out of the bore, Chamber brush to clean the chamber by hand, and CLP to clean and lube everything else, including leaving the upper bearing area on the wetter side with CLP for break in. Do some reading on how to clean and lube the rifle correctly, including the correct solvents to use, and chances are the problem is gong to go away. http://www.ar15.com/forums/forum.html?b=3&f=7 Now if all the above is correctly being done, then the next question is if the bolt is locking back on the catch after the last fired round out of the mag, with the ejection distances of the spent casings being 10' to 15' out? Bring use up to speed this far on the above, and we can take it from there. |
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I feel that I clean my rifle very well every time I shoot, but I will pay close attention to detail when cleaning tonight and each time after. What are some superior cleaning chemicals, lubricants, and solvents that are used commonly that are well known for a good job?
The jam doesn't occur in any particular patters of time. Sometimes it's the 1st shot, sometimes its the 10th or 20th ect... in a random type fashion. When a mag is depleted the bolt always locks back and ejection distances from the rifle are consistent of 10' to 15' |
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Myself, I use Sweets solvent to clean the bore to remove the copper fouling since Sweets does most of the work without a lot of scrubbing, CLP to clean the Chamber with a chamber brush, and the chamber fouling and the any Sweets still in the bore shoved out the muzzle, then CLP to clean and lube the rest of the rifle. On the B/C, strong coat on in inside and out with CLP, a quick flick to knock off some of the excess lube, then the B/C in the rifle with a few dry cycles to allow the CLP to migrate. Also, don't forget to clean the receiver extension tube, and use a light coat of CLP there as well.
Besides the bore and the chamber that need to be cleaned each time, the rest of the rifle just gets a CLP lube change at cleanings for the most part. Also, clean the mags when you get them new with CLP, then maybe every thousand round from then on. A good source of CLP is Break-freeCLP in the 16oz spray can for under $10, and when the rifle decides that it want to act a fool, and start jamming, pull the B/C and give it another wet coat of CLP. CLP has a cleaner in it, and will go to work on the fouling without you have to do anything. P.S, Even if you can get your hands on LSA (used to maintain some of the larger platform weapons like the Mk-19), it lacks the cleaning agent of CLP, so stay away from using such unless that is all you have on hand. It was once used for the M-16 platform way back in the early 60's, but since it did not clean fouling for a dam (read on it's own). CLP was designed for the platform instead. |
| If you think its a feed ramp problem I open the ejection door and slowly feed a dummy round to see it when it starts to point towards the chamber if it clears the flat spot on the upper and starts to engage on the feedramp on the barrel extension... If you see the bullet hit the upper then I would have the feedramps extended to the lower.... Its quite easy to do just be carefull and copy the ramps on the extension..... I have purchased uppers always with M-4 cuts and only built one A2 without but still cut then in and polished just in case... Other than that if you know its clean and well oiled then I would look at the mags and try a diffrent brand... I always use magpuls since I had problmes with the metal GI issues and never have had a hickup with the magpuls with windows... |
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being that you built this yourself, my first guess is that something ain't put together right. assuming proper upper receiver to barrel feed ramps, alignment of the buffer tube, gas tube/port, staked bolt, and cleaning/lubrication methods:
1)test your mags in someone elses AR 2)is it the same ammo that's causing this issue? i use CLP for cleaning my rifles & pistols because i don't let them get dirty enough to need a stronger solvent, only exception is Wilson Combat ultimalube on slide/frame wear points of my handguns. if i do need more cleaning power I use Hoppe's #9 solvent or any nitro solvent. |
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