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Posted: 9/11/2015 1:18:12 PM EDT
| My older DPMS AR-15 carbine has started double feeding lately, it will fire almost a full mag with no issues then start double feeding. I've tried different magazines mainly Magpul and Aluminum GI 30 rounders. Any ideas what may be causing this issue ? |
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Double feeding as is two live rounds out of the mag jammed in the action,
Or do you mean jamming, with one spent case in the action not ejected out and a live round feed on top of that? As for if two live rounds, that one is always the mag the problem alone. Granted that a worn buffer spring can make the problem worse, it still comes back to the mag itself the problem to begin with. Often to solve this kind of problem with a mag and you know that it should still be good, just pull the mag apart and CLP clean all its parts (hence the fouling inside the mag has gotten to the point that is binding the follower from being able to cleanly move in the mag body. If the later with a spent case, and a live round instead, Start off by pulling the charging handle all the way back, and see where the face of the bolt stops against the back of the ejection port window. The face of the bolt should be stopping about 1/8" to 1/4" in front of the back edge of the ejection port window, hence not flush with it, nor retracting behind it. At this point its a good idea to pull the rifle down for a good cleaning, including making sure to scrub the chamber with a chamber brush and CLP. On a high count barrel, after you think that the barrel and chamber are clean, break out a 30cal mop give it a few drops of CLP and spin it in the chamber pushing deep into the chamber. When the mop is removed, if it has any fouling on it, then you are sucking at getting the chamber clean (last chamber cut), and trim to break out the chamber brush and CLP and this time get the chamber clean. Also on a older rig, it a good idea to give the Gas tube a good shot of CLP from inside the receiver until the CLP flows out of the barrel gas port in the bore. Got only knows that amount of carp over the years of cleaning the barrel that has been shoved up into the gas block passage to dry and start clogging the gas system there, and the CLP allowed to soak for a day, will disolve this mess and the first shot through the barrel again, will just blow that mess back into the carrier gas section where it can easily be cleaned the next cleaning instead (don't try to shove anything solid down the gas tube). Also when doing this, look for any CLP that may be leaking out from the gas tube to gas block and even gas block to the OD of the barrel (should be none). Next with bolt in hand, see what kind of tension you have on the extractor spring. If you have a round count of say 4K or more on the rifle since the last spring change, than the rifle is due for at least a new buffer spring, and may be time for a extractor spring swap as well. Extractor pulled, run your finger down the extractor claw and make sure it's still sharp. If it has been dulled from use, then add it to the list of items that are long over due during a normal servicing. As for one the B/C has been cleaned, pull the bolt upwards, set the bottom of the carrier on a table, and if the bolt will not stay up under it's own weight in the carrier, then add gas rings to the items that that need to be replaced as well. Note, ring test is the bolt weight itself, and not the other way, seeing if the rings will hold the weight of the carrier up instead. And again, or lastly depending how you are looking at it, Cleaning and lubing the rifle with the right solvents is real importain. If you are using say hoppes to clean the rifle, when you use CLP to lube it, the Hoppes residue that is left over and the CLP mixing will mix is to a pine tar that will choke the rifle out quickly. So, bore itself gets cleaned with a solvent that will not leave behind a protecting coating (Sweets copper solvent works fast without a lot of needed scrubing to first clean the bore, then CLP is used to clean the chamber with a chamber brush, and when the fouled CLP from the chamber is pushed out of the chamber and down the bore out the muzzle with dry patches, the trace amount of CLP still on both surface is more than enough for short term storage of the rifle. In regards to the rest of the rifle, think of it as more of just a oil change, hence out with the fouled CLP since it has a cleaning agent in it, and in with the New fresh CLP instead. Hence with the rifle going fine for the first mag, then start choking out on more mags, its a solvent problem, and you are using the wrong solvents to clean and lube the upper bearing surfaces on the rifle, with enough fouling collected by the chamber (and maybe even upper receiver bearing areas) via the solvents like Hoppes residue to start causing a lack of B/C full stoking instead. |
| Thanks for the reply, I've tried mags that I know work and the issue still occurs. As far far as cleaning, I clean my firearms after each range outing and don't mix cleaning solvents, I usually use Breakfree for all my cleaning and lube. I will check how far the bolt retracts and clean the gas tube out for insurance. I also have spare buffer spring I can swap out to try as well. |
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