I sincerely doubt that you'd go through 60 rounds of ammo. Wouldn't some of that weight be better spent on a JJ or two?
On the contrary I think 60 rounds will run our pretty fast. It is the only weapon and it generate no heat, so you'll hopefully shoot constantly. But I agree abut the jets, I'd downgrade the engine to 225 to add one. (that being said, his build is troll)