Having AR cycling/feeding issues.

T

TheM4chef

Regular
Rating - 100%
201   0   0
Location
Southern Gulf Islands, BC
Hey folks so finally got up to the range to shoot my new carbine. Had some issues, one of the guys here today was helpful but the problem persisted.

First issue.
Bolt failed to opperate after first round.
Took the ff grip and the gas block was loose. So we tightened that up and then fired again.

Second issue.
Once gas block was tightened set against the cut out of the barrel when i charged the rifle i would get a light hammer strike eg no boom. Once we moved the block forward a but like 1/8" i was getting a fail to extract as well as a double feed. Supsected it was over gassed?
We moved the gasblock incrementally to narrow down the port a bit. I also swapped my colt bolt into the bcg to see if that made a difference. It started to work and the 2mags I put through out were ejecting around 4oclock or so almost the same as the Colt.

Tried another shooters pmag with some steel case ammo
And then the problem of not extracting and the double feed happened again.

Also it seemed that the rounds were catching on the groove on the feed ramps. A lot of copper buildup there.

The bolt I swapped out worked just fine in the Colt. I'm lost right now. Any suggestions? I hope I'm describing the situation properly.

Specs are:
10.5" S&J barrel
S&J m16 bcg
Nea low profile gas block (I believe) it cant butt up against the cutout on the barrel see above.
Carbine gas tube
Winchester 55g fmjbt .223

Help please lol. I can take pictures or describe things better if need be later tonight.
Cheers
 
Last edited:
Possibly either your LP gas block or barrel's gas port is misaligned is my guess. Hate to say it but when you toss in NEA parts into the mix, sad to say that that part usually gets red flagged.

Another wild guess, maybe the gas tube port on the gas block isn't reamed deep enough so the gas tube is hitting the back of the gas key of the BCG, preventing the BCG from fully closing?
 
enefgee said:
I'd check he gas block - perhaps try something by another maker - I hate to say it but he only brand that you have, that also gets knocked for quality is NEA
Click to expand...

S&J gets a pass on a lot of stuff here on CGN. Especially their self-disassembling barrel/barrel extensions. You'll notice the gun worked after adjusting gas block location, so the NEA gas block works.

To the OP, who put your gun together?
 
The lower came assembled from a fellow cng'r and the upper was bought from another 3/4 assembled.
The guys on another forum have strongly suggested a adjustable gas block and all the ftf and fte issues that sound similar to my issues that I've read about seem to recomend that and a heavier buffer.
 
I would try to close the bolt carrier group on a dummy round or head space gauge. If you do this with the upper separated (or just open) from the lower you can actually see the lugs turn into a fully locked position and can verify lock-up. OR loosen gas block, then close bolt fully. Now see how far you can push your gas block on, and if it can be positioned correctly. If not, something is out of spec... gas block, or gas tube length. Something that would prevent full closure of your bolt. What else could possibly have these effects as you move the gas block around??

I would really use a head space gauge set when assembling a gun anyway.. but I am anal that way :) Not that head space is the issue here, just an IMHO type of thing.

good luck
 
You must log in or register to reply here.
Back
Top Bottom