Ok. Only part that should contain your ammo is LCE (load carrying eq) or the "suspenders with the belt. You have two ammo packs holding 6 30rd mags and 4 grenades, two canteens, gas mask, bayonet, first aid kit and compass pouch. That’s your basics. Big ALICE pack will have your half of the shelter, pole, mat, ponch, chem. suit + hood, trenching tool, sleep system, and spare socks, undies, toiletries, private stuff and clothes; all this is put into watertight bag. Pack can be ditched and you have to have all the important gear on you. LCE is always on you during combat even if you got rid of your pack.

BUT

Depending where you are (location) and what your MOS is (job) or what the mission is parts of your pack will be replaced and changed. For example you don’t need a 0 degree sleeping system while fighting people in Georgia climate. On extended missions you will have to put extra ammo there, maybe MRE packs and hope you get re-supplied. If you are a medic besides your own stuff you will carry med pack. If you are a water pur. unit you will have your chemical sets. GIs buy a lot of crap when they leave for war in the PX store . And most of that stuff gets ditched in the field later on because every pound counts.

Being on the field during FTX (field training exercise) is great because it basically is like a big camping (sometimes). You can bring all the stuff you want, you get fed and on top of that you know when you coming back to the barracks. Being in the field during war is horrible since everything is uncertain. And than you realize that things you took for granted such as foot powder, sweat bands, deodorant, soap and smokes are hard to get and you regret that super sniper face mask (useless) took space of the foot powder that you need so much.