Shane,
The Beta C-mag is a modular, double snail drum system, adaptable to many rifles that use a box-type detachable magazine. The manufacturer makes a series of "mag well" adapters that attach to the double drum portion of the C-mag, allowing the conversion of the C-mag to fit many different rifles, which have non-interchangeable magazines. Contact the Beta Co. or have your local police supply house order the appropriate adapter(s) for you.
I personally would question the wisdom of adapting this double-drum magazine to a bull-pup configured rifle. I would expect the drums extending to the sides would make it difficult to handle and aim the gun, since they would be hitting against the ribcage in either the left or right hand firing positions. Perhaps using the AUG with the heavy barrel and bipod in a support weapon role (prone position) would better facilitate its use with the C-mags.
