[tunabreath]

If it's spinning but not coming out, you could try removing the inner barrel first - if it is in fact a burr problem, it'll be easier to pull out the inner barrel which only has the burr scraping as resistance vs the outer which has the burr and the inside of the 'barrel hub.' The inner barrel/hopup chamber is held in by two small phillips screws at the back, one on each side. (careful with these, it's VERY easy to strip the plastic out)

Did you only loosen the hex grub screw or completely remove it? The AUG front outer barrel has a lip that the grub screw secures against which would allow the barrel to rotate but not come out.

I really wish TM had used a two piece metal barrel... While the front end is completely secure, even with only that grub screw holding it, the back half is just plastic with an aluminum sleeve inside, and held very poorly by two philips screws. I'm starting to get a fair amount of wobbling without the obscene amount of tape shimming I've done to the hub/vert grip section.