Big Problem with my AR-15

[cr5]

Holy heck who is selling gas rings for $10 at a 10,000% markup so I know who to avoid buying from forever?

The point was that it's easier to try a simple cheap fix than pay to ship it back and wait for it.
If it was working before and is now short stroking while everything else seems fine it's probably something minor that can be fixed at home.

And if you factor in gas money to get to a gun store and back home they're probably getting close to $10 for a set.

Gas rings look fine no difference in how they look compared to my other AR.

They'll look fine even when they're worn out. Holding the assembled BCG with the carrier in one hand and holding the bolt with the fingers of your other hand is there some resistance to moving the bolt in and out? Should feel similar to your other BCG.

I was referring to the inside of the carrier where the bolt slides in. It should be smooth and shiny in there, if it's not smooth it would explain worn gas rings.

 

[shoota]

Testing the gas rings is easy to do. Either pick up the BCG by the bolt in the locked position or set it vertically on a flat surface, bolt end down, in the unlocked position. The rings should be able to support the weight of the bolt carrier and prevent it from changing position.

As mentioned, there is no need to stagger the gas rings.

hahah the BCG that works fails this test, the one that doesn't passes.

 

[RifleDude]

Have you tried swapping the bolt from the working BCG into the non-working carrier? That will tell you if it's the bolt carrier or the bolt. I suspect it's the carrier that is giving you the trouble.

 

[cr5]

hahah the BCG that works fails this test, the one that doesn't passes.

Is your cam pin cracked and jamming up?
Weird that the rifle works with another BCG but there doesn't seem to be anything wrong with this one.

 

[*MALICE*]

Testing the gas rings is easy to do. Either pick up the BCG by the bolt in the locked position or set it vertically on a flat surface, bolt end down, in the unlocked position. The rings should be able to support the weight of the bolt carrier and prevent it from changing position.

As mentioned, there is no need to stagger the gas rings.

Thats not the correct test, and many bcg's with perfectly good rings may fail that test.

You take the cam pin and firing pin out, hold the carrier with the bolt facing down, and the bolt should not fall out of the carrier.

 

[shoota]

Will try to find some gas rings locally and try that before returning. Will update.

 

[JayCarver]

Just swap the bolt only and try that to save some time?

 

[shoota]

Just swap the bolt only and try that to save some time?

No local places have gas rings so this is my plan now to do a bolt swap.

 

[FoxAlpha]

No local places have gas rings so this is my plan now to do a bolt swap.

Call up tier one armory, im sure they'd be happy to toss a set in an envelope and send it out to you.

 

[shoota]

Update: Swapped bolts and same issue so that rules out bolt/gas rings. Something else looks like it's going in for warranty repairs.

 

[FoxAlpha]

Update: Swapped bolts and same issue so that rules out bolt/gas rings. Something else looks like it's going in for warranty repairs.

It has to be the gas key then.

 

[rambones]

clearly its in the BCG

Not Bolt/gas ring, so its Bolt carrier.

Post a pic of the Bolt carrier. specifically around the gas key front and sides

 

[Green75]

Have you changed your buffer weight or spring? What you described sounds to me like your BCG is not able to travel to the rear far enough to strip a new round, and return with enough inertia to go into battery and lock the bolt.

 

[AB_blaster]

Have you changed your buffer weight or spring? What you described sounds to me like your BCG is not able to travel to the rear far enough to strip a new round, and return with enough inertia to go into battery and lock the bolt.

The OP has swapped carriers between two rifles and the same carrier is the problem. The OP has also swapped bolts between carriers and the problem has been narrowed down to the carrier. The OP's issue is not with his recoil spring or buffer.

 

[shoota]

Snapped some pics.

 

[cr5]

Is that carbon buildup inside the carrier in the last pic? Or scratches/gouges, looks uneven on the bottom?

 

[shoota]

Is that carbon buildup inside the carrier in the last pic? Or scratches/gouges, looks uneven on the bottom?

small bit of build up and just the lighting, smooth as anything on the inside and no scratches when I did a full clean.

 

[SNAFU84]

Have you tried standing up your upper receiver (with muzzle pointed to the ground) and dropping your BCG into the receiver to see if it drops into battery properly? With or without the charging handle. If you have the rifle completely assembled and cycle it a few times, does it feel as smooth as the other BCG's you have? Could it be a gas/gas key and fitment issue as well?

 

[Andy93]

Could just be the photos but is the gas key straight?

The first and second picture look a little off to me, though the third looks fairly straight.

Looks to me that the front of the gas key is cocked towards the extractor side. You have wear marks on the front extractor side of the base of the gas key and the back on the opposite side. I have a S&W BCG with a little higher round count and it doesn't have those marks.

Might be nothing but could be dragging when fired, any angle could cause the BCG to torque to one side and cause the dragging to be worse than if you are just manually moving the BCG.

Might check the upper for signs of wear.

 

[Sarge_DL]

Long shot: Any chance you have a litle scale to see what both of thise BCGs weight? If the the one that is not working is heaveir, then you’d need to change either buffer weight, spring weight, or the amount of gas going into the BCG.