Yes, a realistic answer to run 'n gun tactics -- and we need it all the more, now that ammo limit is gone.
The n00bs may be n00b-turtles now, but they'll be heavily armed turtles blasting away with tons of ammo...and they probably won't use the Minimi once its novelty wears out -- they'll use SIG 551 and FAMAS on "30-round burst" or the AKMSU with drums.
If we make the weapon overheat and, depending on the RL behavior, jam/lose accuracy, such behaviour would be curtailed sharply.
I know the team said no jamming, but random jamming is different from overheated jamming, ne?