the military definitely do use the term loadout. It can be based on mission parameters e.g. if armored vehicles are expected, your loadout might include more MANPATS. It can also refer to the way each soldier might customize their gear, e.g. cutaway knife in boot or on vest, NODs if extended night operations expected (I know, I know, gamers would like to think you'd bring everything, but in real life no warfighter would want to carry extra weight unnecessarily!), or even the placement of gear on their MOLLE vests (all that velcro has a reason).