AR Frustration.

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Would anyone know what would cause an AR bolt to not close all the way when trying to chamber a round? Both my Brother and I experienced this on FIVE AR rifles today at the range.

We were using both factory, and reloaded ammunition that I painstakingly loaded myself.

This was in BOTH .308, and .223 versions.

In the case of my personal AR rifle, I had just given it a thorough cleaning. Usually this helps the rifle operate BETTER. Not in this case apparently. I have had over 800 rounds through it BEFORE I ever cleaned it, and NEVER had a problem with it. It ran perfectly when it was filthy.

Also, when the bolt(s) incompletely chamber the round, it 'locks' closed, necessitating the use of a rubber mallet, and a block of wood to open the action.

The rifles were all a perfectly clean as possible, bolts, chambers, gas tubes, etc etc.

My Brother has had this probelm before, but not as pronounced, and I have NEVER had it before.

Would anyone know what the problem may be, and what the remedy is?

Different magazines were tried as well.

Today was not a good day at the range.

Thanks all.
 
OP
nwo
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That is a good idea yes. I made sure to oil my bolt after I cleaned it. Perhaps I did not oil it enough? Perhaps all FIVE ARs were not oiled enough? That is certainly possible. How much oil is enough on an AR?
 
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Light coating don't soak it. When you remove the BCG and shake and snap the bolt does it slide and pop back and forth or is it stiff? I had a AR15 BCG that was real stiff give me some trouble a while back. If the BCG is moving smooth and isn't binding when you check it you might have some type of issue in the chamber where its trying to lock. also check the gas tube it could be slightly warped or bent. be careful using reloads it will often cause issues and will void warranties.

Reco
 
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When you say five ARs, do you mean 5 complete rifles, including uppers, lowers, etc. no sharing of parts?

I've had the problem when I bent the **** out of my charging handle. There was enough of a bind between it and the gas key that it would fail to go into battery.

While I haven't seen it with an AR, I have seen an Sig556 bolt bind on the top of the mag causing a problem.
 
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nwo
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When you say five ARs, do you mean 5 complete rifles, including uppers, lowers, etc. no sharing of parts?

I've had the problem when I bent the **** out of my charging handle. There was enough of a bind between it and the gas key that it would fail to go into battery.

While I haven't seen it with an AR, I have seen an Sig556 bolt bind on the top of the mag causing a problem.

Right, five separate AR rifles. 2 .308s, and 3 .223s. No sharing of parts at all.

The bolt(s) are all 'loose' and not binding. All 'shake' loosly without being stiff at all.
 
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nwo
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We "think" we have it figured out. All of the ammo used was either factory commercial stuff, OR my reloads using commercial brass AND military brass. The rifles ate ALL of the commercial factory, and commercial brass reloads. They DID NOT like the reloaded MILITARY brass. So, no more MILITARY brass will be used in reloading. Only commercial stuff.
 
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Light coating don't soak it. When you remove the BCG and shake and snap the bolt does it slide and pop back and forth or is it stiff? I had a AR15 BCG that was real stiff give me some trouble a while back. If the BCG is moving smooth and isn't binding when you check it you might have some type of issue in the chamber where its trying to lock. also check the gas tube it could be slightly warped or bent. be careful using reloads it will often cause issues and will void warranties.Reco
I think you offered some good advice but I take exception to the bolded part. I have several thousand rounds through my AR with 90% being reloads. They are just as reliable as store bought ammo in my experience. Also, I probably overlube my bolt/BCG but I also rarely ever have any issues with it ... in fact I can't remember the last issue I had. Guess I'll find out here in three weeks when I go to my AR class at Oregon Firearms Academy. 1200 rounds in two days should be a decent test for it and my cleaning/lube procedure.
 
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It is not the military brass. I would bet that your reloads are not sized properly, do you check and set your dies with a cartridge case gauge? It is very important to use a case gauge with any semi-auto. I have reloaded 5.56 for years and can't stress enough the importance of using case gauges on all cartridges you load to ensure proper chambering. IF some of your reloads were commercial brass and some were military, then I would say it is because military brass is slightly thicker and your sizing die may be sizing the commercial brass ok but the military being thicker, your die adjustment may be slightly off and not moving the shoulder of the case back far enough. Buy a case gauge and check your reloads, I bet they are to long. This is the only reason an AR would lock up so tight you have to beat it open.
 
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I think you offered some good advice but I take exception to the bolded part. I have several thousand rounds through my AR with 90% being reloads. They are just as reliable as store bought ammo in my experience. Also, I probably overlube my bolt/BCG but I also rarely ever have any issues with it ... in fact I can't remember the last issue I had. Guess I'll find out here in three weeks when I go to my AR class at Oregon Firearms Academy. 1200 rounds in two days should be a decent test for it and my cleaning/lube procedure.
Have to agree here, how safe do you consider factory ammo lately with all the recalls they are having. I trust my reloads much more than factory ammo.
 
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It is not the military brass. I would bet that your reloads are not sized properly, do you check and set your dies with a cartridge case gauge? It is very important to use a case gauge with any semi-auto. I have reloaded 5.56 for years and can't stress enough the importance of using case gauges on all cartridges you load to ensure proper chambering. IF some of your reloads were commercial brass and some were military, then I would say it is because military brass is slightly thicker and your sizing die may be sizing the commercial brass ok but the military being thicker, your die adjustment may be slightly off and not moving the shoulder of the case back far enough. Buy a case gauge and check your reloads, I bet they are to long. This is the only reason an AR would lock up so tight you have to beat it open.
I agree that it's probably improperly resized cases. Get a case gauge like stated earlier. I'd also get a headspace gauge so you can actually measure if the shoulder has been bumped back. If you don't want to spend the money, then do some research on the method that uses a permanent marker.
 
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Well military brass is for 5.56mm so unless your AR chambers have 5.56 or mulitcal on them then the rounds throating won't fit properly once you reload them. I'm guessing that the rounds are too long as well since it happened on 2 AR10's.
 
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I had a similar problem with some used brass i got from a range. Get a dillion case gauge and compare the suspect brass to new factory brass. There is more to it than just the length of the brass. Even if you trim the brass and resize it might not work properly.
 
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1.) Trim your cases to the minimum overall length.

2.) Full length resize the brass with a Small Base Resizing Die.

3.) Lubricate the rifle and bolt carrier group per these drawings and your problems will go away. Bill T.

AR-15RifleLubricationPoints-1.jpg

AR15BoltCarrierLubePoints-1.jpg
 

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