Jamming AR-15

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lebl468

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Cold Lake AB
Hey, all, I checked the stickies, but didn't see anything about stoppages. My AR has developed a habit of jamming on the first round it cycles itself. What I mean by that is that I will cycle the action to chamber the first round, fire, and the second round will jam in the upper, with the bolt resting against the round sitting at an angle in the upper. It almost seems like it is having trouble picking up the round out of the mag, so I tried 5 different mags from different manufacturers, and no dice. The lower is a used Olympic, upper is a new Wilson. The first 50 rounds I fired through had no stoppages, then it progressively got worse. Now it is guaranteed to do it every time. I am shooting 55gr JHP's over 26gr Varget. The closest I could figure would be short stroking, cause it feeds fine when manually cycled. Any insight would be great.

Chris
 
Last edited:
Quite likely short stroking, and it could very well be your load.

Varget has a habit of being kind of inconsistant from lot to lot.
25 grains in one lot could be right on the money, and the next lot, you could find yourself struggling to stuff 26 grains to get the same velocity.

Regardless, that load you are running isn't one I'd be going with. I would recommend something faster with a 55gr. bullet - something in the H335 or TAC speed - and I'd probably say 25gr. is a starting load with those powders.
What does it chrony at?
 
beltfed said:
Quite likely short stroking, and it could very well be your load.

Varget has a habit of being kind of inconsistant from lot to lot.
25 grains in one lot could be right on the money, and the next lot, you could find yourself struggling to stuff 26 grains to get the same velocity.

Regardless, that load you are running isn't one I'd be going with. I would recommend something faster with a 55gr. bullet - something in the H335 or TAC speed - and I'd probably say 25gr. is a starting load with those powders.
What does it chrony at?
Click to expand...

I will try some different loads, but all of mine have come from the same bottle of powder and it started off good. I am still leaning to a mechanical problem.
 
lebl468 said:
Using CLP for lube. I thought that might be a problem, but it was pretty warm this weekend and it still was acting up
Click to expand...

personally I would get a box of factory 55gr fmj and see if you could hammer them off. I have not got into reloading yet but was told auto loaders are very finicky and require precise tolerances
 
So the fired case is properly extracted and ejected? How far does it go?

Does the fresh cartridge get clear of the mag lips, or is the head still in the mag with the bullet halfway up the feed ramp?

Does the feed ramp profile of the barrel match the upper?

I second trying a box or two of factory FMJ.
 
i've seen it before and there were two causes. one is the wrong buffer spring (the regular buffer spring in a m4 tube) or cleaning swabs stuck in the base of the buffer tube.
 
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