Simple solution - replace the uppers and mags with 6.8 SPC ones. Replace the Humvee with the M113A2 as we used to use in the 70s.
Wounding an enemy depletes more enemy resources than killing them.
The Humvee was not the replacement for the M113, but rather for the Jeep. The M113 replacement is the M2/M3 Bradley fighting vehicle. I'm sure you'd much rather be in a Bradley than in an M113. It's faster, has better armor, and is armed with a 25 mm chain gun. It can also carry the TOW, under armor, in case you come up against some Gomer in a tank, AFV, or just need a bunker busted right quick. Of course the Humvee can carry a "naked" TOW as well.
I'm also sure you'd rather be in a Humvee, which can have some armor, than a Jeep, which had none.