The Dragon II is ideally used at longer ranges while the Colt Commando is a short range weapon, so they don't really mesh well together. If you were to use Rangers (Dragon) to target enemy vehicles at ranges greater than 500 meters, they'll only have 2 M249's to fight off any enemy infantry that come along.
#Replace the Colt Commando with M16A2 for Rangers (Dragon)
wary flare
still siren
agreed, but only if the commando stays for the LAW squad
torpid comet
The commandos are really good at close range, personally prefer to use mech rifles for longer range and the rangers more for CQC with the benefit of better AT than engineers.
marsh frigate
If you want a unit that’s good at distance use Mech Rifles (Dragon)