My DA556 is jamming, need help.

thump_rrr said:
Yes but they can wear out as you can see in this pic comparing a new gas tube to a worn one.
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But wearing of the 'flare' won't cause build up of debris inside the tube.......

Nor will it cause the problem the OP is having since the gun isn't short stroking.

:)
 
*MALICE* said:
But wearing of the 'flare' won't cause build up of debris inside the tube.......

Nor will it cause the problem the OP is having since the gun isn't short stroking.

:)
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I never claimed that there could be buildup or debris inside the tube nor did I claim that tube wear was the cause of his failure.
I simply stated that the tube shoud be inspected for wear.
BTW the end of the tube is not flared. It is the same as the major diameter of the gas tube. The gas tube is turned down just prior to the end of the tube.
 
BTW the end of the tube is not flared. It is the same as the major diameter of the gas tube. The gas tube is turned down just prior to the end of the tube.
Click to expand...

Hence the quotation marks on 'flared'

I never claimed that there could be buildup or debris inside the tube nor did I claim that tube wear was the cause of his failure.
Click to expand...

Since you replied to someone else who was replying about cleaning the gas tube, I erroneously assumed you believed a dirty gas tube could be the culprit. I was obviously mistaken

:)
 
something just got to me, this being DA, does your upper receiver have M4 like feed ramps ? If yes, then you'll have to keep looking but if not, that is one thing that would hamper feeding. This could work or not in combination with different magazines. Some mags just naturally feed reliably, some need the rest of rifle to be top notch and still need some mag tweeking.
 
IMR4320 said:
something just got to me, this being DA, does your upper receiver have M4 like feed ramps ? If yes, then you'll have to keep looking but if not, that is one thing that would hamper feeding. This could work or not in combination with different magazines. Some mags just naturally feed reliably, some need the rest of rifle to be top notch and still need some mag tweeking.
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The reason it's not feeding is because the spent case is staying in the chamber and the next round slams into the back of it.
 
NoTarget said:
Sure, I will just ask which one of my kids doesn't want to play hockey this year. I like guns but they are far from my #1 priority.
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Simple the one you don't like as much doesn't play hockey this year :p

NoTarget said:
Thanks for the advice guys. I will try to scrub the chamber/feed ramps really well and new ammo next trip to the range.
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You can try, something tells me your gas port is messed up. Let us know how it goes.
 
My other suggestions is that your gas block/port is leaking and the rifle is short stroking enough to grab a fresh round but not enough to fling the brass out. Check around the gas block/ front sight tower, perhaps even smear some grease in the area. Fire a few rounds and see if any grease has been displaced.

This may have already been covered but, you did ensure your ejector moves freely and is still good an stiff?

TW25B
 
rdavidson said:
Do you have pic of the bcg
Gas key
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Yes, see post #19

TW25B said:
My other suggestions is that your gas block/port is leaking and the rifle is short stroking enough to grab a fresh round but not enough to fling the brass out. Check around the gas block/ front sight tower, perhaps even smear some grease in the area. Fire a few rounds and see if any grease has been displaced.

This may have already been covered but, you did ensure your ejector moves freely and is still good an stiff?

TW25B
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I was experiencing the same problem when I replaced the entire BCG from my M4gery. The 14.5" runs fine.

One thing I never mentioned is my rifle flings the brass hard to the 5 o'clock position. The rifle doesn't have a brass deflector and if a lefty shot it they would constantly have brass thrown in their face. I did a quick search on the internet and this seems to suggest that the rifle is over-gassed. Anyone know where I can get a replacement rifle buffer? Are there heavier models for rifles that might slow down the cyclic rate?

I scrubbed the chamber to make sure it's clean and tried to take a picture of the feed ramps.
320662A2-127F-4018-8250-5DCFF990FBC7_zpsravdiuka.jpg

A7FB3C02-D080-4591-8E12-E9B2AD7D1F5A_zpsttonivfx.jpg
 
He is most likely getting a full stroke, as the rifle is stripping rounds. OP- load one round in your magazine and fire it. Does the bolt lock to the rear? If so, it's definitely not short stroking.

If it's over-gassed it should still extract fine, especially on a longer barrelled AR. If it was a shorty with a carbine length gas system it could be unlocking too quickly when the brass is still expanded in the chamber due to an early and violent pressure spike. This would normally show torn or deformed rims on your brass from where the extractor made contact.

The fact that it ran fine and now doesn't makes me think it's either chamber roughness/build up or extractor. What extractor spring did you use when you replaced it?

When you clear the jammed round with the bullet pushed into the case, leave the case that's stuck in the chamber alone. Pull your charging handle back and let it fly home. Can you eject the case easily by racking the charging handle by hand? If so it will eliminate the chamber as suspect and point back to the extractor or gas system.

The dwell time on a rifle length gas system is fairly long so I can't see the over gassing causing this, but I've been wrong before.... A lot.
 
Checking out the rims on the extracted ammo in post #32, I'm not seeing any damage that would suggest stuck brass in the chamber (the rims aren't mangled by the extractor). That suggests that the extractor isn't gripping the round when it's fed in. Have you checked to see that there's not a piece of brass (or something else) under the extractor in the bolt?

It's possible that you could have a worn extractor as well. OP, did that extractor upgrade kit include a new extractor, or was it just a spring, silicone piece, and an O-ring? If the extractor is worn or broken, it won't grip the rim and the round sits in the chamber.

Can you post a pic of the extractor itself, taken out of the bolt? It might help diagnose the issue.
 
Throttle_monkey1 said:
He is most likely getting a full stroke, as the rifle is stripping rounds. OP- load one round in your magazine and fire it. Does the bolt lock to the rear? If so, it's definitely not short stroking.

If it's over-gassed it should still extract fine, especially on a longer barrelled AR. If it was a shorty with a carbine length gas system it could be unlocking too quickly when the brass is still expanded in the chamber due to an early and violent pressure spike. This would normally show torn or deformed rims on your brass from where the extractor made contact.

The fact that it ran fine and now doesn't makes me think it's either chamber roughness/build up or extractor. What extractor spring did you use when you replaced it?

When you clear the jammed round with the bullet pushed into the case, leave the case that's stuck in the chamber alone. Pull your charging handle back and let it fly home. Can you eject the case easily by racking the charging handle by hand? If so it will eliminate the chamber as suspect and point back to the extractor or gas system.
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There are no marks on the brass and it ejects easily after I remove the magazine and pull the charging handle.

shredder said:
Checking out the rims on the extracted ammo in post #32, I'm not seeing any damage that would suggest stuck brass in the chamber (the rims aren't mangled by the extractor). That suggests that the extractor isn't gripping the round when it's fed in. Have you checked to see that there's not a piece of brass (or something else) under the extractor in the bolt?

It's possible that you could have a worn extractor as well. OP, did that extractor upgrade kit include a new extractor, or was it just a spring, silicone piece, and an O-ring? If the extractor is worn or broken, it won't grip the rim and the round sits in the chamber.

Can you post a pic of the extractor itself, taken out of the bolt? It might help diagnose the issue.
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I have replaced the extractor, the extractor spring and added the plunger and O ring. I am having the same problem as before the replacement. I used a DPMS extractor and an upgrade kit I purchased from CTCS.

At this point I don't think it's the extractor but I could be wrong.
 
No Target, have you tested this yet?

norlandgeese said:
I read your thread, try this as a test to isolated the problem.
You have another AR I hear, which is working fine I presume. If it's compatible profile, take this problematic one's upper receiver only (basically empty receiver and barrel) and stick it on the other AR (complete lower and BCG) and test it. Use as much of the other AR as possible.
If exact same problem still occurs you will be quite certain it's either you barrel&chamber or the receiver.
Any unusual wear marks inside the receiver?
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You may have a BCG which is not making a full stroke into battery that is sufficient enough to have the extractor claw grip over the rim however pushes it into the chamber. When fired it travels back without the spent case and cycles the next round on top of it.

Check by manually cycling a single round from the magazine with the bolt release , then slowly pull back on the charge handle to see if cartridge extracts and ejects. Also try to cycle the BCG into battery on a cartridge by very gingerly allowing a full stroke while holding onto the charge handle. Check to see if it goes into battery without the help of the forward assist. Once chambered pull back again to see if it ejects.

Another item that may be contributing to it is an ejector pin malfunction. Check to see if the pin retracts into the bolt allowing the extractor to grab the rim. An ejector spring may be broken, bent or very dirty hindering smooth movement.

The head space may have been changed by over powered rounds or God forbid the barrel extension may have come loose.
 
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