FYI Im seeing DPMS uppers costing in the mid to $800 range. You might be able get a complete rifle for nearly the same cash. It's crazy. DPMS has been having some good factory direct sales but Ill bet their delivery time frame blows.
Long, thin and flexible, Ill bet the standard gas tube works without much issue. I checked the DPMS parts pages and there isnt a special tube listed. Cash permitting Im hoping to get a Fulton stripped upper by Xmas and put this all to rest.
With so many manufacturers jumping in the 308 game It's no longer black and white DPMS vs AR-10. For parts availability and the best mags I believe DPMS is currently the best choice. Just don't buy a DPMS stripped upper. Go with Fulton Armory or somebody else. From what I hear Armalite parts availability is improving. Mags are limited and pricey. A good place to start for non Armalite AR-10 is Rainier Arms.