The Army and Marines have used the M240 for years. It's the standard platoon level machine gun. They don't have to dismount them from the vehicles. The dismount kits for the M240 thats the coax gun in the Abrams and Bradley is very hard to come by. If they dismounted the M240 from the turret, it's most likely unusable in a ground mount role.
I bit more info on this: The coax variant of the M240 family is the M240C. In order to be used in an infantry role, you'd have to replace, at a minimum, the following parts:
1) backplate-the 240C has a backplate, not a buttstock
2) pistolgrip/trigger group-in the coax role, the 240C's trigger is actuated by a solenoid. The grip on the 240C is greatly shortened, long enough to get about one finger below the trigger guard.
3) barrel-not really that hard to do, but necessary, since the 240C doesn't have any front sights
Not sure if you'd need to replace the feed tray cover, since I don't remember if the 240C has rear sights on the cover or not. The 240C also feeds from the right-not necessarily a problem, but not the norm either.
I also don't remember if the 240C has a full-size charging handle-in the Bradley and M1, you use a cable with a loop on the end to charge the weapon. I don't remember exactly how it's attached.