Ar 15 Not Cycling

[GreenfieldGunny]

I recently posted about my AR15 not cycling, I tried the most of the suggestions people had posted but my AR still will not cycle properly. When I first built my AR15 it worked flawlessly, I fired around 500 rounds through it without problem. I recently had a new gas block and free float handguard installed at Bradis. Took it to the range the next week and it functioned perfectly for around 100-200 rounds. Cleaned it the same way I have since I built the gun, took it to the range the following weekend and it wouldnt cycle any of the ammo I used. I was using PMAGS, shooting Xm193, 62g Wolf and 55g LC surplus. I have completely cleaned the rifle several times since and it still wont cycle. It will fire the first round and eject it but wont chamber the next. Occasionally it will cycle the 55g LC Surplus ammo.The bolt is leaving scratch marks on the 2nd round. I am not really sure what to do not besides taking it to a gunsmith. Any ideas?

[So IN Dude]

First, fire one round and see if it locks back on empty mag, this will rule out short stroking or undergassed problems. It sounds like your gas port may be blocked. Check to see if your gas block has moved?

[esrice]

Originally Posted by So IN Dude

Check to see if your gas block as moved?

This was my first thought, since he just got a new gas block installed, and then ran 200 rounds through it before the problem cropped up.

[GreenfieldGunny]

Originally Posted by So IN Dude

First, fire one round and see if it locks back on empty mag, this will rule out short stroking or undergassed problems. It sounds like your gas port may be blocked. Check to see if your gas block has moved?

I did just that, the bolt didnt lock back. As far as if the gas block as moved, I dont know. It looks to be centered properly.

[Donnelly]

I'd bring it back to Bradis where you got the new gas block installed and tell them what's happening and see if they can help. It definitely sounds like you are losing gas somewhere. Gotta be the block or the tube.

[esrice]

Originally Posted by GreenfieldGunny

I did just that, the bolt didnt lock back.

Ok. Then that tells you that you are probably short stroking due to inadequate gas.

Originally Posted by GreenfieldGunny

As far as if the gas block as moved, I dont know. It looks to be centered properly.

Given your first sentence, its probably off just enough to cause your short stroking.

Have shooter521 at Bradis take a look at it and he'll get you squared away.

[mammynun]

While I agree that it's probably a wandering gas block, I'd check to ensure the gas key is tight before jumping in your POV... you probably already did, but with the price of gas I figured I'd throw it out.

[GreenfieldGunny]

Originally Posted by mammynun

While I agree that it's probably a wandering gas block, I'd check to ensure the gas key is tight before jumping in your POV... you probably already did, but with the price of gas I figured I'd throw it out.

Gas key is tight, I check it during cleanings. I guess I will be going to Bradis soon.

[shooter521]

Sorry to hear you're having problems. If the carrier key is GTG, the only other things I might suggest checking before you bring the gun back in are the gas rings, and where the gas tube enters the gas block. If the rings aren't damaged and there is no sign of excessive outgassing, we will go on the assumption that your gas block has shifted a bit.

Did I do the install, or was it Dave? What kind (brand/style) of gas block is it? New tube, or did we reuse your existing one? Answers to these questions will let me start working out possible causes and solutions prior to the gun coming back in.

Let me know when you plan on coming in; I'm normally off Thursdays and Sundays, but would be happy to take a look at it any other time.

[GreenfieldGunny]

Originally Posted by shooter521

Sorry to hear you're having problems. If the carrier key is GTG, the only other things I might suggest checking before you bring the gun back in are the gas rings, and where the gas tube enters the gas block. If the rings aren't damaged and there is no sign of excessive outgassing, we will go on the assumption that your gas block has shifted a bit.

Did I do the install, or was it Dave? What kind (brand/style) of gas block is it? New tube, or did we reuse your existing one? Answers to these questions will let me start working out possible causes and solutions prior to the gun coming back in.

Let me know when you plan on coming in; I'm normally off Thursdays and Sundays, but would be happy to take a look at it any other time.

I installed McFarland 1 piece gas ring as I was advised by a friend. But that was installed when the rifle was built and is not damaged at all. The gas tube going into gas block has alot of black around it, not sure if this is normal. But when I was inspecting it seems as if the gas tube roll pin wasn't installed. I cannot remove the gas tube as there is no roll pin it must be jammed in the gas block. I slightly loosened the set screws holding the gas block but the rear set screw was rounded so I couldn't check to see if it was misaligned. The gas block is a Midwest Industry low profile block, it was new. The gas tube was reused. It wasnt you, some guy with a beard? Dont remember his name.