Newly built AR's: Failure to Feed?

[halfmileharry]

Upon further inspection, the gas block was both a millimeter from the barrel stop and slightly offset. I've readjusted it. What are the odds this was the cause of the problem?

Probably 1:1

 

[sig1473]

Upon further inspection, the gas block was both a millimeter from the barrel stop and slightly offset. I've readjusted it. What are the odds this was the cause of the problem?

Like Harry said, the odds are high. How good/deep is your dimple for the gas block? If it isn't deep enough, this would be a cause for the misalignment.

 

[kolob10]

I have had several friends with the same issue over the past year. In every case, All I did was realign the gas block. This is probably a common mistake among new builders.
The issues were with 1 458 SOCOM, 3 .223's amd a 300 Blackout. Good shooting!

 

[NyleRN]

Upon further inspection, the gas block was both a millimeter from the barrel stop and slightly offset. I've readjusted it. What are the odds this was the cause of the problem?

Possibly, but I don't think that's the problem. The hole in the gas block is quite a bit larger than the gas port in the barrel. I've taken some apart and you can see by the carbon ring around gas port that the gas block wasn't perfectly alinged but the gun still ran just fine because there was no overlapping

 

[halfmileharry]

Upon further inspection, the gas block was both a millimeter from the barrel stop and slightly offset. I've readjusted it. What are the odds this was the cause of the problem?

one mm forward or back most likely won't give you an issue. How many gas blocks have been installed for free float handguards AFTER removing the handguard cap (Forward collar).
However just a slight twist will cut the gas flow in half in a heartbeat.

 

[croy]

Upon further inspection, the gas block was both a millimeter from the barrel stop and slightly offset. I've readjusted it. What are the odds this was the cause of the problem?

From your very first post my guess was gas block alignment. I've had to fix several myself.

 

[TheDude]

This should be tagged for the rifle section. Good info here.

 

[FamilyProtectR]

Just a quick update: the issue I had on a 556 was mag related. I had a similar issue on a new 300blk, but it's now solved. After running 30 rounds through it slowly over the last two trips to the range, I had many failure to feed issues. I believe it was tied to subsonic ammo and a new buffer spring. After I worked my way though 30 rounds, I popped a mag full of another 30 and they all fed perfectly. I believe the combination of a little bit of wear on the spring and a little bit of breaking in the feed ramp, and I'm good to go.

 

[markiemark]

Glad to hear you are back up and running. I had the same issue with my 300 blk. Tried several things and it ended up being the gas block misaligned. Time to send more rounds down range!