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Posted: 1/18/2014 9:16:09 PM EDT
| I recently built my first ar I think I have shot maybe 150 rounds through it its a black hole weaponry barrel 16" with a saa upper saa bcg on a rock river lower with rock river look yhm free float hand guards So I have been having problems with it jamming I it's pretty inconsistent sometimes it feeds sometimes it jams I have noticed the feed ramps are scratching the bullet pretty bad on the jammed rounds I have been shooting cheap Tula 223 rounds until my order of 556 comes in from psa I am using magpul p mag magazines I had tried my dads pro mag magazines and the failed horribly sometimes the bolt wouldn't even catch a new round to jam I don't believe it's a short stroking issue because the bolt will catch on the last round with the magpul magazines but not the pro mag also I thought it might be the feed ramps having a burr on them because there was a slight burr so I tried to clean the up with the dremel which is I bad idea I know that now after doing research I didn't take any metal off that I could tell just the coating on the feed ramps before I got kinda scared and decided to do some research. so actually this is a two part question could I have screwed up my feed ramps with the dremel and is it just crap ammo and my ar needing to be broken in more or do I need to fix something I have also already checked the buffer and spring and they are correct |
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The cheap ammo could be the problem for break in,
But lets back up, for break in, you want to keep the upper bearing areas wet with CLP. Also to note, you should be cleaning most of the rifle with CLP as well (barrel bore [not chamber] itself if the only thing that needs a good copper solvent like Sweet's instead). Also not a bad idea to pull the mags down and give them a good CLP cleaning as well. Next on the hit list, the chamber has to be cleaned via a chamber brush with CLP, scrubbed by hand before the rifle is even fired, and every cleaning. The fact that you are using Poly coated ammo, which the coating will get scrapped off the cases, and deposit the powderized poly coating on the chamber wall, means that you really need to go to town with the chamber brush during cleanings. No standard gun solvent will dissolve the powderized poly fouling, so the only way that you can get it out of the chamber is to scrub it out with a chamber brush. As for the barrel feed ramps, great choice not to pick up the Dremil!!!!!! But before we do anything about end of feed ramps burs, first determine if you have the right upper to barrel extension in play. 
If the upper and the barrel extension match, and you do have end of barrel feed ramps burs that you can visiable see, then these burs can be removed with nothing more than a chop stick with a slip in the end, tuck some 400 sand paper in the slot and wrap it around the chop stick, and us such to remove the tip burs. Now to add, when you hand cycle out a live round, it will be scrapped, and it not coming from the barrel feed ramps. As the round is being pulled back out of the chamber by the extractor, once the tip of the round clears the barrel breach, the ejector cams the tip of the round to the right, and it get dragged off the right hand barrel lug on the way out. This is a normal scrap on a bullet when being cycled out by hand, since you tell that the scrap starts at the back of the bullet, and ends at the front of the bullet due to the end patterns in the scrap groove. 
A scrapping at feeding looks more like this from end of ramp burs, since the scrapping starts at the front of the bullet, and then back, 
Last two items, Make sure that the mag catch threaded section tip is flush to the face of the mag release button, And regarding mags, the Key here is real USGI mags, and not some cheap knock off clone mags that will cause nothing but problems. If you where wondering, real USGI mags go for under $15 in the EE section here,so got to wonder why some guys are still buying some craptastic clone mags instead. |
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