feeding problem please help

[xnv733x]

i recently finished my first ar 15 build after i pull the charging handle with a chambered round i pull the trigger once the round is fired and extracted smoothly i am then left with the bolt completely forward with an empty chamber and hammer cocked back i dry fir it and have to pull the charging handle to chamber another round also upon testing the mag lock out it doesnt seem to lock the mag consistantly (sometimes after pulling the handle with an empty mag it does not lock out ) could this be anything besides a defective mag by the way its made by sabre defense thanks in advance for any help

[MILLITIAof1]

sounds like the bolt is not moving far enough back to strip another round from the magazine(short stroking)

[MILLITIAof1]

there are numerous causes of short stroking
underpowered ammo
carbon build up
not enough lube on the bcg
the list goes on and on, time to troubleshoot your rifle

[xnv733x]

i was using remington 55g fmjs out of 60 rnds it did this about 90% of the timethere were two ocasions where it fired about 5 in a row before i had to pull the handle again and it was just cleaned and lubed today could it be short stroking even though it was extracting smoothly

[xnv733x]

considering that the bolt travels far enough rearward to extract the empty cartridge can i rule out short stroking

[The Cable Guy]

considering that the bolt travels far enough rearward to extract the empty cartridge can i rule out short stroking

No, the empty casing can still eject if the BCG isn't all the way back.

[Jicko]

Is that a BRAND NEW upper? If so, please give it a thorough cleaning! And the lube the BCG, and make sure the gas rings on the bolt is not-aligned to each other.

With the upper off, make sure that your magazine is "activating" the bolt-catch when it is empty. Also, make sure that your bolt-catch is moving freely, put some CLP around the bolt-catch slot.

Lastly, when everything is cleaned and is well lubed, do this 100-200 times before your next range trip.
- with an empty magazine, pull your charging handle back until the bolt is locked back, and put the charging handle back
- release your bolt via the bolt catch
- dry fire
- repeat

[Seesm]

Sell that pile to me "CHEAP" and build another... Yeah that's the ticket...

[xnv733x]

it was used and i cleaned and lubed it today before taking it out is there any chance it is just the mag thanks for all the help

[EOD3]

I have an Oly upper in 7.62x39 mated to a SunDevil lower that ejects the magazine if it's not seated FIRMLY. Next time it happens, give the magazine a good tug to make sure it's fully seated.

[Dragon]

IF its used ,may be the gas rings need to be changed .

[J_Rock]

Is that a BRAND NEW upper? If so, please give it a thorough cleaning! And the lube the BCG, and make sure the gas rings on the bolt is not-aligned to each other.

Even if the gas rings are aligned it wont cause any problems. The AR15 can run on 1 gas ring if needed. Its very long and perpetuated myth about the AR15

[xnv733x]

i just completely disassembled the bcg after removing the bolt half of a broken ring fell out of the carrier i am planning on purchasing a new bolt any advice on which one to buy and from where

[Jicko]

Even if the gas rings are aligned it wont cause any problems. The AR15 can run on 1 gas ring if needed. Its very long and perpetuated myth about the AR15

From what the OP found out, the hard way, obviously there are some merit to the myth....

With 1 of the rings failed, that's what it take to make OP's gun not work.

[J_Rock]

From what the OP found out, the hard way, obviously there are some merit to the myth....

With 1 of the rings failed, that's what it take to make OP's gun not work.

From Pat Rogers:

"Replaces conventional three-piece “piston ring”-style sets that can accidentally line up, causing a major leak from the gas expansion chamber in the carrier."

That is absolute bull****.
It is no more than a myth that has turned into reality.

For many years the Colt Amorers course (when they used to do live fire) used a single bolt ring and the gun worked fine.

I have fired a buttload of rounds with a single bolt ring.

I learned to stagger the bolt rings in the Marine Corps because they were repating what the FM told them.

We know better now.

Bolt rings can wear, and should be replaced at interval. A one piece ring is no better/ worse than 3 single bolt rings.

The key here is to check them regularly and replace when necessary.

But staggering them? A big waste of time.

I can imagine that it was the broken piece that gummed up the works not the lack of a gas ring. I'm sure someone much more knowledgeable will come around and set the record straight. Obviously this would be very easy to test out for yourself