Got it put together, now time to troubleshoot (7.62x39 AR)

[lftd&pwrstrok'n]

Finally got the 7,62x39 AR together and just tried shooting her. Failed to eject on each round. Picked up the empty casing 3/5 times, but did not eject. Did not pick up empty casing 2 times and tried to load round behind it. Got 4 rounds off before calling it quits. Very first round was a stovepipe, but after that none of them made it out of the chamber before jamming. Where do I go from here to figure this thing out? nicaburns @Allsmiles @Countryboy 1980

Build is as follows:
Anderson upper/lower w/ Magpul Moe stock/grip and DSG lower parts kit
Advanced Research 16" barrel/BCG combo: (7.62 AR-15 Complete Bolt Carrier Group and Barrel Combo)
Omega 15" hand guard: (http://www.deltateamtactical.com/Om...Slim-Keymod-Ar-15-Handguard-Rail-_p_4383.html)
Davidson Defense gas tube: (http://www.deltateamtactical.com/Da...um-Gas-Tube-Ar-15-Carbine-M4-Ar15_p_4089.html)
Omega muzzle brake: (http://www.deltateamtactical.com/Om...MS-LR-308-LR-308-AR-10-762-Muzzle_p_4033.html)
Gas block: (Micro Low Profile Gas Block for .750 O.D., steel)
Wolff heavy hammer spring
KNS pens

 

[lftd&pwrstrok'n]

It almost seems like the action is too slow. Is there a difference in port size for the gas block on the 7,62 and 5.56? Gas tube different?

 

[rOmiLaYu]

The first three things that I would check are as follows.

1) gas block alignment. The system sounds like it could be undergassed. Are you sure the holes line up?

2) extractor. Check the cases and look for wear on the rings. Are you sure the bolt is grabbing hard enough on the case as it moves rearward?

3) gas tube alignment. If you put it in upside down, it kinks the line and the rifle is undergassed.

 

[Rgrbulldog]

Gauge it. Make sure it locks up tight.

 

[rOmiLaYu]

It almost seems like the action is too slow. Is there a difference in port size for the gas block on the 7,62 and 5.56? Gas tube different?

Port sizes in barrels vary even within the 5.56 chamberings...anywhere from .07X to .09X. But the hole in the block will always be bigger than the one in the barrel so a standard block and tube will be fine, provided they are installed correctly.

 

[lftd&pwrstrok'n]

The first three things that I would check are as follows.

2) extractor. Check the cases and look for wear on the rings. Are you sure the bolt is grabbing hard enough on the case as it moves rearward?

I only picked up 2 of the spent cases; they both have pretty noticeable scratches/marks on them.

 

[nicaburns]

The first three things that I would check are as follows.

1) gas block alignment. The system sounds like it could be undergassed. Are you sure the holes line up?

2) extractor. Check the cases and look for wear on the rings. Are you sure the bolt is grabbing hard enough on the case as it moves rearward?

3) gas tube alignment. If you put it in upside down, it kinks the line and the rifle is undergassed.

^^this^^
One fix if it is option 2 is just a stronger extractor spring but sounds undergassed. Bolt is likely not making full rearward cycle.

 

[rOmiLaYu]

I only picked up 2 of the spent cases; they both have pretty noticeable scratches/marks on them.

On the walls or the lip of the case?

 

[nicaburns]

I only picked up 2 of the spent cases; they both have pretty noticeable scratches/marks on them.

That is the .223 width feed ramps... Hog those suckers out

 

[rOmiLaYu]

That is the .223 width feed ramps... Hog those suckers out

Yeah, that's what I was getting at.