Ok dumb question, this is my first AR. Failure to eject spent casing question.

[SideShow Bob]

To quote a member here "Sausages have Casings, Firearms have spent Cases...... "

The gas tube should not move, it is pinned (or should be) to the gas block / front sight tower which ever the case may be, with a roll pin.
You are probably losing gas pressure at the front of the tube.

[reticman]

I meant that I loosened the front sight that the gas tube is fixed in and moved that down the 1/4" after adjusting the hand guard. You are correct the gas tube does not move freely otherwise.

[SideShow Bob]

As GK mentioned in your moved thread, a better discription and more information is needed, and perhaps a picture too.

Just a guess, you had a misaligned gas port in the barrel to the port in the gas block if you were able to move it down a 1/4 inch.