For all you scrubs that doubt the US support weapons, let me tell you this.
Locked and loaded Infantry T4 is like one of the best support based T4s ive used in a long while.
It is the american equivalent to the Terror Heavy support.
Locked and Loaded makes your machineguns very beefy. The +25% HP, +20% acc. and +10 sight goes along way into making the US machinegun an offensive beast.
These bonuses coupled with T2 Steady sights allows your machinegun to mitigate accuracy penalties at all ranges from moving infantry provided the machine gun is set in cover. The sight bonus allows it to spot for itself and fire at max range all the time, and the HP gives it staying power to be used offensive.
Old MG acc. vs. stationary infantry: (L/M/S) 0.2/0.4/0.75
L&L+ SS acc. vs. stationary infantry: (L/M/S) 0.27/0.55/1.035
Start calculating in vet bonuses and you got some stopping power for your MGs
Personally I am pairing my 3 MG squads with a Thompson ranger a piece and they've been working great because of the Support Traning T3 moving acc. bonuses making the rangers keep on the move but still killing stuff as if they were standing still.
I would also like to say that if you love snipers, then Locked and Loaded is for you. The extra 35% dmg is nice allowing you to destroy i believe even KCH, but the awesome sauce here is the +10 sight bonus, so you can spot for yourself. The HP boost also keeps you from getting biked also. Ive been running 2 and got both to vet 3 in 4 games with around 25-50 kills a sniper. The one that is still alive is 2nd on the leaderboards atm.
Also, AP rounds for the 57 on cooldown is a godsend. I currently dont have enough munis for all of my ATGs, but L&L gives some nice bonuses to the Stacking shells T2 and I might just switch over and drop the howie because whatever a howie can take out, the snipers can use better.
Here's my Launcher. It should be more full of vet MGs but I just got done with a tough game. (I lost the apprentice sniper but the master is still kickin)
I really urge you guys to give it a try, its a very underestimated T4.