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New Ar-15 keeps jamming/fails to feed.

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New Ar-15 keeps jamming/fails to feed.

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Old 12-12-2017, 01:23 PM
  #1  
Spike
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Default New Ar-15 keeps jamming/fails to feed.

I just got a new Ar-15 and I cant make it past 5 shots withought it failing to feed or jamming. I know it cant be the bullets or the mags bc i have tried 3 different brands of bullets and 3 different brands of mags. What should i do? I'm considering returning it but I was wondering if its something that can easily be fixed. Thnx.
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Old 12-12-2017, 01:39 PM
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clean it, then clean it again
RR
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Old 12-12-2017, 02:08 PM
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What kind of jamming are you getting? When it fails to feed, is it failing to pick up out of the magazine, or is the round overshooting the top of the chamber?
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Old 12-12-2017, 03:11 PM
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I agree more info on what is NOT happening or happening causing jams

DID you CLEAN gun before trying it and oiling as required?
as that alone can be an issue
some guns come from the factory with excessive dirt or OIL/Grease
and IF
if your shooing LOW velocity rounds THAT can be the issue too., even if different brands(seen many AR's have issue with Steel cases rounds too, or just lacquered coated cases for that matter)
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Old 12-12-2017, 03:44 PM
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It ejects the bullet but closes completely withought grabbing a new bullet. Also, it sometimes ejects the bullet and halfway chambers a new one. I cleaned it and im only shooting brass case. If i knew how to post a pic I would.

Last edited by Juston; 12-12-2017 at 03:53 PM.
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Old 12-12-2017, 06:52 PM
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When you say it half chambers the next round, is the base of the next cartridge under the bolt, or in front of the bolt?

Based on your statements, I'm assuming the former, and in that case, it sounds like you're short stroking. Does your rifle lock back on an empty mag?
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Old 12-13-2017, 04:25 AM
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It usually doesnt stay open when the mag is empty. The base is under the bolt
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Old 12-13-2017, 08:29 AM
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If it's not locking back, and not picking up rounds, then it's short stroking. Here's a copy/paste of some of my AR troubleshooting notes, for reference for you and others.

It's a machine, so malfunctions are systematic. Only a few things can cause short stroking, failure to pick up, and failure to lock back (in no particular order):

1) Over length buffer bumper. Test: Can you pull the charging handle far enough to lock the bolt back by hand? If yes, then this is not it. If no, cut/sand the tail of the rubber bumper to give you sufficient clearance. The forward face of the bolt should draw approx 0.25" behind the bolt catch when fully rearward. If the bolt travel is gritty, exhibits any catches, or presents significant drag, there may be some other damage or dimensional interference between the BCG, buffer, and receiver extension - this should reveal itself in the buffer length test.

2) Out of Spec Magazine. In this case, the mag sits a little higher in the well than it should, so the top of the mag lips drag on the bottom of the bolt. Tests: try a different mag. You can also "paint" the top of the mag and/or bottom of the bolt with layout fluid (Dykem) or a magic marker then cycle the bolt on top of it, looking thereafter for witness marks. Another test: load one round, drop the mag, then fire while pushing on the tail of the bolt catch. If it cycles fully and locks back, you have a contact problem.

3) Insufficient bolt travel during cycle, typically due to improper gas system performance. This can be a loose gas key, poor gas ring seal, out of alignment gas block, plugged gas tube, undersized gas port, insufficient dwell time, under powered ammunition, and gas leaks in the system (block to barrel, block to tube, tube to key, key to carrier, and gas rings). Tests: Much of this can be checked by pulling the upper, removing the BCG, inserting an empty case into the chamber, and blowing into the muzzle to feel for resistance. Look for carbon blast marks around the block on the barrel, on the gas tube where it inserts into the block, and on top of the carrier where the key is seated. Also inspect the end of the gas tube and the mouth of the gas key for carbon build up or torching. Confirm the gas rings are in good shape, and confirm the gas key is tight to the carrier. Clean the gas system thoroughly, and try again. You can also plug the gas tube and try blowing again - you can't generate 15,000-25,000psi like your rounds will (rifle to carbine), but you may be able to identify a gas leak which hasn't left witness carbon - with the chamber and tube plugged, you shouldn't be able to blow through the muzzle. This is most likely your issue.

4) Insufficient mag follower travel. This can be caused by dirty mags, weak springs, warped/damaged mags, or under spec mag well. The mags aren't elevating rounds quickly enough to beat the bolt. Test: try a different mag. If a new mag works, clean the old one, check the spring and replace if necessary, or replace the whole mag. Really don't expect his is it for you - but it could be if your first few rounds run fine when the spring tension is at its highest, but then failures start happening. If you feel friction inserting the mags, you likely have mag bulge or an under sized mag well.

5) Excessive action drag. Similar to the out of spec mag problem above, if the bolt isn't traveling freely, it might fail to pick up. Usually this also presents itself by failing to close very frequently, as the rearward force in the cycle is much greater than the forward closing force. Tests: You should be able to feel excessive friction when cycling the action. Again, if you aren't getting failures to close, only short stroke failures, then friction is unlikely. A thorough cleaning and proper lubrication will solve this problem.
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Old 12-29-2017, 07:48 AM
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NoMercy that article above should be put in a sticky. Very informative. Now with that being said, if I were Juston, I would take the rifle back where he bought it and have the situation resolved either through refund, replacement or returned to the factory for repair.
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Old 12-29-2017, 08:37 AM
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That's a very good point. Personally, I prefer to do as much of my smithing and repairs on my own, but the easiest answer with a factory AR is to let the mothership solve the problem they created. Even if I DO send a firearm back for repair or replacement, I like to know what should get fixed when it gets there, to be sure it actually gets fixed.

There are two downsides to sending one back to keep in mind: 1) time in transit - if it's a simple mag problem or fouling/lubrication issue, a good cleaning or a new mag will get it running in a matter of minutes. Most major manufacturers will have you without your rifle for a few days of shipping at both ends, plus at least a week in house, sometimes longer. I can usually identify and fix any issue within an hour, so I don't like to send stuff back for a couple weeks if I don't need to. 2) their test ammo may not match your real world ammo - if they run high octane test ammo and it runs fine, they'll send it back and say all is well. You'll still have a problem with your ammo when it gets back - then you'll get frustrated that they didn't do anything and it still doesn't work and maybe send it back and the same thing happens again, or maybe on the 2nd or 3rd trip they say to send some of your ammo back with it... months down the tube (item 1), and they still didn't fix anything yet. This usually ends with an online thread (or dozens) where the owner bad mouths the companies customer support and swears off the brand forever, whereas it's a simple issue of differing ammunition selection...

But overall, the easiest route will be to send it back to the mothership to let them sort out the issue - just be aware of the two items above, and don't turn into "that guy" who swears off a great brand simply because they're running lighter ammo than the rifle was designed to use.
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