Get a medic truck, any gun that requires two soldiers,
a tank, two officers/snipers, and a supply truck. Have the two
officers/snipers operate the gun, then order a tank. Fire just
one shot at the gun, then immediately press C. After the
supply truck fixes the gun, use the medic truck to take the gun.
Then, take the gun off. There should be one more officer/sniper.
Repeat as much as needed, but the game may crash if done too many
times.