Ar-15 jamming issue?

Question

I have a black rain ordnance spec 15 ar-15. The gun worked flawlessy until about 300 rounds in with American eagle green tip 62 grain 5.56. After that every few rounds the gun would jam. It would fail to eject the spent shell completely and either not catch the next round or jam it with the spent shell in the action. After contacting the manufacturer they said to try a different ammo. So i bought pmc 55 grain and it worked flawlessy. I went to the range a few days ago and used 55 grain american eagle and same issue as previously. Any idea on why the gun is doing this? Also how come i was able to ise the 62 grain in the beginning but not anymore?

Answer 1

Welcome to the world of the Jam-o-matic.

Answer 2

I had a similar problem. What I eventually figured out was that my extractor spring was extremely weak. Put in a new extractor spring and it was fine. Another thing I can think of is the gas rings might be damaged.



Cleaning it wouldn't hurt. However I went in entire year and a half without cleaning one of mine. I just kept putting motor oil through the holes on the side of the boat carrier. When I finally did clean it because I was bored it The inside looked like you would expect: covered with thick black Oily gunk. But it never jammed once on me in that state.

Answer 3

Real shame you did not include any info on your experience with this type of rifle or how you have been cleaning it.



So, go buy this book on Amazon and read it:

https://www.amazon.com/AR-15-Complete-Owners-Kuleck-2014-05-03/dp/B01FEKBMQ6/ref=sr_1_2?ie=UTF8&qid=1487780763&sr=8-2&keywords=Complete+ar-15+guide



There is a companion book by the same authors for building AR's that is worth every penny. You should probably buy that also while you are there.

Answer 4

Have you cleaned and lubricated your gun after the initial 300 rounds? Have you field stripped and inspected the rifle since the problem occurred? Did you look for any unusual wear or damage? What magazines were you using and did you experience this with one or more magazines? From the provided information alk I can suggest is to clean it and use PMC and other ammo that cycles well.

Answer 5

Failure to eject, is your problem.

It's not likely to be an ammo problem. The manufacturer just said that to deflect blame in case it's a factory defect.



Take a look at the mechanisms involved with extraction and ejection. The extractor and it's spring and little rubber buffer thing as well as the ejector and it's spring.

The extractor is your most likely culprit. When it fails to hold onto the cartridge well, it can slip off prematurely and cause what you describe.





If that stuff all seems good, then check to see if it's cycling well. I've seen failure to eject and feed failures from magazines which are out of spec and rubbed the bottom of the bolt carrier. It's also, theoretically though not as likely, possible for a lack of lubrication to slow the bolt carrier enough to mess up the extraction/ejection sequence.



Finally, and least likely in my mind, would be a burr in the chamber causing the brass to get hung up upon extraction.

Answer 6

Alix, you wrote " not catch the next round or jam it with the spent shell in the action" two things that cause this, a dirty or faulty extractor or a dirty chamber. Clean it first and check for damage to the extractor or spring.

Answer 7

Check your gas rings. The first thing you ALWAYS check if your AR short-shucks is your gas rings -- if they are not properly staggered, they will allow enough gas blow-by that lower power rounds will not fully cycle, causing the malfunction you have described.

Answer 8

Check to see if the gas key on top of the bolt carrier is tight. The two allen screws there should have been staked after they were torqued in place. Be sure the chamber is clean before you go back to the range.

http://www.firearmsnews.com/wp-content/blogs.dir/12/files/ar-gas-key-staking/ar-key-stake-2-082712.jpg

Answer 9

Fail to eject or fail to extract? Fail to eject = ejector worn. Fail to extract = worn extractor or missing extractor spring. Not catching the next round COULD be a missing gas tube pin (under front sight). Without the pin the gas is not pushing the carrier back far enough to clear the rounds in the mag. Also, non-staggered gas rings can cause extraction failures.