AR15 Function issue

[Ex E6]

Have a friend who's having issues with stove piping ,sometimes ejected case lays backwards in the ejection port ,sometimes jumps piggyback on incoming round . Unit had 5K rounds down with No apparent issues at Xmas ,then he began experiencing problems . Changed BCG ,as figured extractor spring was weak . NO GO . Cleaned like inspection day ,even removed gas block , NO help I suspect it's a gas issue as springs are and were changed NO help possibly Bolt excessive travel ?. However locks on empty mag. . Most puzzling predicament . What say all Armorers ?. Thanks up front , BushMaster

Nobody has any ideas on possible culprit interfering with ejection function ?

 

[longshot2000]

Honestly, with that round count, it is time for a tune-up, probably. I would take the gas tube apart, clean out the gas block and soak and air hose the tube, dunk the upper and lower into degreaser, take everything apart, clean, replace parts that are worn, oil and put it back together. I would give the bolt carrier all new parts except the bolt, but new extractor springs, o-ring, the works.

 

[6.5SH]

Check the condition of the rubber tip on the buffer and the depth of the travel on the carrier into the receiver extension (buffer tube).
If the bolt face goes back much past the rear of the ejection port something is wrong with the above.

This is likely where your backwards fired cases are coming from.

 

[Ex E6]

Honestly, with that round count, it is time for a tune-up, probably. I would take the gas tube apart, clean out the gas block and soak and air hose the tube, dunk the upper and lower into degreaser, take everything apart, clean, replace parts that are worn, oil and put it back together. I would give the bolt carrier all new parts except the bolt, but new extractor springs, o-ring, the works.

To the best of MY knowledge ,owner has pulled everything including GB tube Bolt stripped cleaned inspected ,then replaced BCG so as to check weak extractor scenario suspicion . NO go same problem , changed buffer spring . Assured NO carbon or gunk is anywhere and ran it wet ,then wiped it down . Ejection issue still exist . I personally suspect ejection is deflecting at 0:12:00 or 05:00 thus slapping port and not ejecting ,I've Never seen it but something is amiss .
I'm certainly NO expert but have assembled a dozen AR's 10's as well as 15's in various calibers ,had a few issues here and there but Nothing not curable by component change or modification . This is certainly a puzzle to which something is either being overlooked or is defective . What is the $10K question ??. Thank You

 

[Ex E6]

Check the condition of the rubber tip on the buffer and the depth of the travel on the carrier into the receiver extension (buffer tube).
If the bolt face goes back much past the rear of the ejection port something is wrong with the above.

This is likely where your backwards fired cases are coming from.

Have NO direct knowledge whether this has been done and will pass suggestion along ,much appreciated . Thank You ;
This is driving MANY bonkers ,as it seems he's done most everything one could imagine relating to ejection issue but to NO avail .

 

[Ex E6]

Owner has ALL info and is under advisement . Hopes to get to the range this weekend and nail down malfunction issue .

Will advise ASAP ,as I hear .

 

[Jgault]

It’s probably not over travel from what you described, besides if it was that bad he would feel it beating the gun to death. If the bcg was changed and I assume it had new gas rings it has to be the gas system. As said above I would try a new gas tube, clean the hell out of the gas block, and make sure the gas port is clean. The only other thing I can think of would be the magazine not feeding correcting and the new round coming out to soon making contact with the spent brass.

 

[Ex E6]

It’s probably not over travel from what you described, besides if it was that bad he would feel it beating the gun to death. If the bcg was changed and I assume it had new gas rings it has to be the gas system. As said above I would try a new gas tube, clean the hell out of the gas block, and make sure the gas port is clean. The only other thing I can think of would be the magazine not feeding correcting and the new round coming out to soon making contact with the spent brass.

Hopefully I'll get a report either during or after weekend ,as to IF any suggestions have rectified his function issues . ? .

I did learn he has a quality setup ,with an excellent lower ; so we're Not talking a bargain bin frankin gun and as said before ran like a champ 5K rounds . Something changed around Christmas and his first action was Cleaning thoroughly and being Ex Military referenced like inspection day .
Later reiterated GB Tube Bolt disassembled ,NO help started changing parts still NO help . My initial thoughts were gas system but after his system overhaul ,including New BCG change . Changed ammo also ran various brands ,still malfunctioned So I'm most curious as to the problem and he's doing #1 fix at a time ,so as to KNOW what it actually is .

I've had worn even torn gas rings ,as I'm sure many of us have and in My case NO malfunction just DIRTIER but bolt got sluggish .

 

[Ex E6]

Still awaiting diagnosis solution results . Seems work has interfered with his range plan ,so hopefully in short order should know something ?.

 

[hlee]

Iphones have a pretty good slowMo video feature. Maybe videoing the ejection will give you some clues.

 

[Ex E6]

Problem resolved : Below a direct response from the owner of problematic AR-15 . My conclusion Buffer and Spring combo , as he had tried nearly everything else save rebuilding the lower . Spring alone wasn't it ,nor was the Buffer ,yet when Both were changed apparently Runs like it did before . So My thanks to ALL who followed contributed and commented along with advice

The standard Sprinco (white) spring, and the H1 buffer... it ran like the good 'ole days! 120 rounds, not one jam. In fact, I would say the recoil impulse was a little less than what I was used to, but that is subjective, of course. I even ran it with the brass catcher... which was a question I had about the last range session. No muss, no fuss... except one thing. Using my old USGI 20rd Colt magazines, the bolt would not lock back on an empty magazine. This has happened before with the old, abused 20's... so I'm not seriously alarmed by it, but next time out I'll make sure I take a PMag, which have always been 100%