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CGK60
05-06-2011, 8:07 PM
Took out the AR ,started jamming again. I put in a new extractor spring still jamming looks like its short stroking. tried my sons bolt in mine ran great,put my bolt in my sons and it started jamming.wonder if the gas rings are bad, not pushing the bolt back far enough.Ready to buy a new bolt?

dieselpower
05-06-2011, 8:12 PM
confused...jamming and short stroking cause two different problems.

Is the bolt going back, without extracting and then NOT trying to feed another round...or is it trying to feed a round when it never extracted the spent case.

if it is trying to feed a new round, then it most likely isn't short stroking...since it went back far enough to strip a round out of the magazine.

a new bolt will not fit this. the extraction could be a chamber issue, needs cleaned, needs reamed, the extractor arm could be bad, fix the extraction first...then look at the feed problem if there is one.

metalliman545
05-06-2011, 8:15 PM
Trash the whole rifle. Ill take it off your hands

Tzvia
05-06-2011, 8:16 PM
Check the gas key bolts- they may be loose. Tighten them and stake them properly. You could replace the rings, but I would bet on the gas key first.

dieselpower
05-06-2011, 8:18 PM
also remember a too light of a BCG buffer and buffer spring can cause the extractor arm to open up when the BCG starts its rearward travel. If the BCG is moving too fast the extractor will "jump" over the rim of the case and fail to extract. The BCG will go back, strip off a new round and attempt to feed it causing a double feed jam.

dieselpower
05-06-2011, 8:21 PM
need you to explain what was happening and why did you change the extractor spring.

8200rpm
05-06-2011, 8:22 PM
http://www.eccentricsleevenotes.com/userimages/DL_Bob_Marley_sleeve_Jamming_Punky_Reggae_Party.jp g

CGK60
05-06-2011, 9:28 PM
replaced becuase it wasn't extracting cases. gas key is tight. some times the case will be stove piped and trying to feed another round.Why would another bolt work.maybe bolt is out of spec.

dieselpower
05-06-2011, 9:40 PM
replaced because it wasn't extracting cases. gas key is tight. some times the case will be stove piped and trying to feed another round.Why would another bolt work.maybe bolt is out of spec.

ok so;

1) some times the case doesn't extract
2) sometimes it stove pipes
3) It feeds.

Since you didn't say these, we should assume
1) It has never failed to ATTEMPT to feed
2) it has never closed on an empty chamber

The chamber could be hanging on to the case causing the extractor to lose grip on the rim. The BCG has the energy to go all the way back, strip a fresh round, but since the extractor lost the case, the BCG attempts to double feed or the case gets caught and dropped then the BCG stove pipes it as it is attempting to feed a new round into the chamber.

Clean the hell out of that chamber, have you been firing tula or wolf?

If the BCG is going back far enough to strip a fresh round, I think the gas system is fine.

I think the Bolt, ejector, extractor and or chamber are junked up and need a SERIOUS cleaning.

FeuerFrei
05-06-2011, 11:38 PM
:confused:
So the malfunction follows the bolt? Or are you swapping the entire BCG?
Are they both AR15 carriers? Or using an M16 carrier? Just curious.
Look for discrepancies in the extractors and make sure the bolt lugs are intact.
Check the ones next to the extractor specifically.
Have you tried shooting 1 round at a time to see if it locks back and extracts?
Can you run air through the gas key. Not clogged?

CGK60
05-07-2011, 8:08 AM
Both BCG are AR-15. I will try one round at a time and see what happens.The BCG is clean. Using wolf and tula and brass cased with the same results.Sounds like I might need a new extractor.

FeuerFrei
05-07-2011, 10:02 AM
Good!
Did your rifle ever function correctly with the original BCG?
When fired, do you see any brass shavings (or steel/wolf/tula) in area of bolt?

CGK60
05-07-2011, 11:13 AM
Yes it doesn't have more than 200 rounds through it.thought it was the clip and bought new one still the same problem.whats confusing it that it runs great with another bolt, 0 jams.

FeuerFrei
05-07-2011, 12:18 PM
Clarity. You say bolt. I read complete bolt and NOT complete BCG.
Bolt and carrier are different. Are we on same page?
Did you notice any of the other things I mentioned before?
Obvious differences? Cracks etc.?

Try swapping JUST the complete bolt and keep all other carrier parts the same.
This will narrow down to whether it is a bolt issue or carrier.
If the malfunction follows just the complete bolt then you have the fix in front of you.

dieselpower
05-07-2011, 12:37 PM
Clarity. You say bolt. I read complete bolt and NOT complete BCG.
Bolt and carrier are different. Are we on same page?
Did you notice any of the other things I mentioned before?
Obvious differences? Cracks etc.?

Try swapping JUST the complete bolt and keep all other carrier parts the same.
This will narrow down to whether it is a bolt issue or carrier.
If the malfunction follows just the complete bolt then you have the fix in front of you.

agreed. swapping the Bolts in the Bolt Carriers. If the malfunction follows a Bolt, the Bolt is bad. If it doesn't or is random its the chamber.

A dirty fouled chamber will cause the expanding case to lodge and get stuck for a microsecond. In that microsecond the extractor has started to pull the case out, but loses its grip, the extractor arm "jumps" the rim and the BCG continues its rearward travel. The case could have enough momentum to to clear the chamber, but the forward moving BCG and fresh round slam into the old case and it stove pipes. The case may NOT have had enough energy to clear the chamber and the fresh round the BCG is trying to feed pushes the case back into the chamber...double feed jam.

A out-of spec chamber can cause this too by being just a hair too small. the build up of junk on the walls causes this problem after a few hundred rounds.

So swap the Bolt in the different Carriers, and then you will know which problem you face.

Hope this helps.

ArkinDomino
05-07-2011, 4:03 PM
I bet its a stag! :D

dieselpower
05-07-2011, 6:10 PM
I bet its a stag! :D

wanna bet?

http://www.calguns.net/calgunforum/showthread.php?t=339720

ArkinDomino
05-07-2011, 6:22 PM
I wish I could have a beer with you...

CGK60
05-07-2011, 6:50 PM
Switched the complete bolt and carrier. I will just switch the bold and see what happens this time will keep everyone posted how it turns out Thank for your help Im new to AR's

dieselpower
05-07-2011, 6:59 PM
Switched the complete bolt and carrier. I will just switch the bold BOLT and see what happens this time will keep everyone posted how it turns out Thank for your help I new to AR's

keep us posted on this. You have been dealing with this for a long time and we do want to get this solved for you.

mattt
05-07-2011, 9:18 PM
Am I to believe a AR isnt perfect,and can malfuntion?What is next Santa isnt real and no Easter bunny:eek:

motorwerks
05-07-2011, 9:33 PM
I cant believe no one has asked (and they may have I only scanned the reply's) are the gas rings staggered?

dieselpower
05-07-2011, 11:09 PM
I cant believe no one has asked (and they may have I only scanned the reply's) are the gas rings staggered?

gas rings can be lined up, the pressure will still unlock the bolt. It may fail to lock on an empty mag, but it will feed. And in this case its feeding fine. The problem is the extraction.

Gunsrruss
05-08-2011, 10:15 AM
Took out the AR ,started jamming again. I put in a new extractor spring still jamming looks like its short stroking. tried my sons bolt in mine ran great,put my bolt in my sons and it started jamming.wonder if the gas rings are bad, not pushing the bolt back far enough.Ready to buy a new bolt?

You may find that your carrier needs to be changed. A cheap fix is to add a little gun oil through the holes on the side of the carrier. After awhile the inside of that carrier becomes scared and it slows down the action. That's when you get short stroking. I had the same problem and trouble shot it down to that. I just ordered two carriers from Brownels for my rifles:)

CGK60
05-08-2011, 4:45 PM
I'm surprised that any part of my BCG would go bad in only 200 rounds.I guess its possible.I'll try another carrier with my bolt and vise versa and see what part of the BCG is bad.