I don't know all but I can tell you that:

20mm goes with all miniguns like the 2 on AC-130 or the F3 on the osprey

25mm goes with US LAV, US Bradley.

18x Rocket tube goes in the rocket launchers on vehicules like the attack littlebird in F1.

12x artillery rocket goes with the US rocket artillery trucks

M2 goes on any US turret like on humvees , styker, or Abrams, it match the (50cal) mention.

120mm shells goes in the main Abrams gun

Grenade box goes in the (MK 19 GL) grenade turret on styker or tripod (placable turret)

The 105mm shell (yellow one) goes in a yellow plane, can't remember the name as I only saw it once.

The bigger yellow shell is for the Howitzer artillery, can't remember if the size is 155mm or else..

Hope this list can help you a little, enjoy.