AR-15 BM. I got the roll pin out but can't get the gas tub out. I need the reuse the gas on another upper.

There is a tool for that job, but it can be done with a good pair of vise grips, with something to cover the grips jaws, as not to bur the tube, but be careful not to crush the tube. Slowly, rock the tube right to left to break and carbon, and as you rock move the tube towards the rear of the upper, when it clears the sight base, remove the vise grips and twist gently and slide forward to the outside of the front sight base, there you have it!

andreusan's right (I don't believe I just said that), it should be that easy.  Don't forget to lube it up well.

There were some Bushmasters a couple of years ago that had the barrels overtorqued.  Make sure the gas tube isn't pressed tightly against the barrel nut etc...  

Some lube/hoppes and that puppy should come right out using the above as a guide.

Thank you, I did however forget the bushy bbls problems.

It is my, shall I say off color remarks and posts that piss off the masses, but it does however make em think some!!!