Well it all depends on what MOS you have.
If you’re a Grunt in a deployable battalion you’re not going to be able to follow any kind of bodybuilding regime.
Most of the time you’ll be out in the field eating MRE’s and in garrison you’ll be doing a lot of running and body weight training.
Most weight lifting will be done in garrison after work.
In Iraq you should have a Gym. My first deployment I was on a company FOB (Forward Operating Base) and we had a decent gym. My second deployment we had a Plt FOB and we bought free weights from the hadjis.
Problem is going to be time and motivation. You’ll be pretty damn tired and now and again you might get dysentery or something like it and lose all your gains or be out for a week straight and only come back for resupplys. On a good note lifting really really helps with the stress and the bullshit and you’ll still make gains.
To summarize this rant, If you’re really dedicated to lifting don’t go infantry. Pick a non combat arms MOS i.e airwing and you can get huge. Grunts are usually pretty skinny.
Best of luck.
P.S I was called Jarhead before the movie. Really self councious about that.