A2 does not cycle

[BPTactical]

Any oil is too much as far as leakage, given the viscosity of oil imagine how much gas is leaking @ 40,000 psi!

Check your PMs

[ERNO]

I had a failure to fully cycle rearward in my AR-15,16 inch barrel;when I installed a hydraulic buffer in my stock.I reinstalled original buffer: problem solved.

[theGinsue]

Lots of great information in these pages. I've got an early model Colt SP1 having a lot of these same issues. I've been too lazy to take this thing apart to the degree I need to TS, too lazy to actually begin, and too embarassed to ask.

Now I've got lots of great info to check out and perhaps get the problem with the SP1 solved.

[esaabye]

Lots of great information in these pages. I've got an early model Colt SP1 having a lot of these same issues. I've been too lazy to take this thing apart to the degree I need to TS, too lazy to actually begin, and too embarassed to ask.

Nopw I've got lots of great info to check out and perhaps get the problem with the SP1 solved.

Looks like I may have found the problem. The smith at bowers pointed out the the carrier I had was (I thing) a SP1 type with reduced area on the bottom. I recently replaced the trigger with a RR 2 stage and the combo is the problem (he thinks but it all fits). I ordered a new M16 carrier with key from Bravo for $65, will know for sure next week.

pic below is colt carrier like mine.

[Quib]

In your OP, you stated the weapon ran fine for about 30 rds, then stopped cycling.

If the issue was a parts compatibility one between the un-shrouded bolt carrier and FCG, I would think the weapon would exhibit these signs from the beginning, and not over a period of time.

[BPTactical]

In your OP, you stated the weapon ran fine for about 30 rds, then stopped cycling.

If the issue was a parts compatibility one between the un-shrouded bolt carrier and FCG, I would think the weapon would exhibit these signs from the beginning, and not over a period of time.

This +1
What was described in the original post was a degenerating condition, as the weapon was fired the condition worsened.
Something changed the more the weapon was fired i.e. gas leak.
The shroud length of the BC is not the problem. If the bolt carrier can travel far enough back to cycle the weapon then the hammer is getting cocked unless the RR trigger group has been monkeyed with.
If the weapon cocked and stayed cocked after the RR trigger group was installed then the BC is not likely the problem. This would be discovered by a basic function check after the weapon was reassembled.

FWIW- I have swapped bolt carriers between all of mine and all cock and lock with either the shrouded and unshrouded bolt carriers.

Interesting-keep us posted.

[esaabye]

In your OP, you stated the weapon ran fine for about 30 rds, then stopped cycling.

If the issue was a parts compatibility one between the un-shrouded bolt carrier and FCG, I would think the weapon would exhibit these signs from the beginning, and not over a period of time.

I do not disagree, but the gas key looks fine and the only difference is the carrier design. I had not noticed the difference until the guy at bowers pointed it out.

I forgot about the change in trigger.

[Quib]

Well, obviously the Carrier swap narrowed down the issue. But, I do not believe the issue is the Carrier being the un-shrouded type.

As BP stated, please keep us posted!


ETA: Did you check the items I outlined on the last page?

Some other possibilities:

- Interior of the Gas Key worn? Causing gas loss between the Gas Tube and interior of the Gas Key? How is the condition of the portion of the Gas Tube that enters the Gas Key? Worn smooth?

- Interior of the Carrier worn? Causing gas loss between the Bolt Rings and interior of the Carrier? Performed the Bolt Ring Wear Check?

[henpecked]

Any updates on this?

[esaabye]

Yes, good news is Bowers' smith (can't remember his name) was right. The issue is the combo of the reduced bolt carrier and the Rock River trigger. For whatever reason the trigger geometry is such that it slows or retards the bolt carrier just a bit and it fails to cycle.

I moved the BC to serveral other rifles and it works fine, just not with the one I shoot. All othyers work fine in my A2, just not the reduced BC and only after trigger upgrade to RR.

I purchased a M16 carrier from Bravo to replace it and moving on. Happy now.

Thanks for all the good info, will come back to this thread in the future for reference.