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tllstaco wrote: Upon further examination, the gas tube appears to be bent or is not aligned as it should be which is causing a momentary binding.

The Gas tube is probably the cheapest part to replace on an AR, so you've got that going for you :)
If it's just bent, you can either try to bend it back, or replace it.

However, if it is misaligned because the hole in the upper is misaligned, then yes, take it back. Your upper is out of spec.

You must first determine which of these two is the problem. the tube itself, or the hole in the upper that holds it in place.

If you cannot take it back, for whatever reason, all is not lost. It will take some work, and a barrel wrench, but you can replace both the gas tube, and the stripped upper fairly easily. The stripped upper will be more expensive than the tube to replace, but not too bad.

dicion wrote: The Gas tube is probably the cheapest part to replace on an AR, so you've got that going for you :)
If it's just bent, you can either try to bend it back, or replace it.

However, if it is misaligned because the hole in the upper is misaligned, then yes, take it back. Your upper is out of spec.

You must first determine which of these two is the problem. the tube itself, or the hole in the upper that holds it in place.

If you cannot take it back, for whatever reason, all is not lost. It will take some work, and a barrel wrench, but you can replace both the gas tube, and the stripped upper fairly easily. The stripped upper will be more expensive than the tube to replace, but not too bad.

I think it is just the gas tube. It is not centered in the hole in the upper receiver. I need to find the punches and a barrel wrench so I can take it apart.

Update 9/27/09: I took the gas block and barrel off today. The gas tube isn't bent. I was surprised that the barrel came off (it's threaded and screws into the upper receiver) without taking the nut that the floating handguard mounts to. Anyways, I found out what the problem is. The hole in the nut that the gas tube passes through is not centered with the hole in the upper receiver. As a result, it forces the gas tube to bend slightly to one side. The nut is on way too hard for me to turn with the tools I have. Ordered a wrench and a vise block this afternoon and they should be here Wednesday.

Update 10/2/09 Today I got my tools and was able to line up the holes. Had to go to a little bit higher torque than 80 ft-lbs. The action is definitely smoother. Hopefully I'll get to try it out this weekend.