AR trouble at the range......

[Ignored Member]

The gas tube on an AR shouldn't get clogged up. Each round is sending enough pressure through it to keep it clean enough to run properly.
I would be willing to bet that the pin holding the tube is missing and has rotated the gas tube a little bit, or the gas block has been canted. Either way the gas tube hole is closed more than it should be causing it to be a single shot.
Take it all apart and reassemble checking each part for failure as you go.

 

[Norman]

Never said it would get clogged. My thinking was maybe there was a *Slight* chance the gas tube was man-handled prior to or during installation which *may* result in a crack. Like I said, not necessary, but it would make me feel fuzzy.