I have had an ALICE pack Large for about 20 some years , I suppose if your were in the military you got used to them , that said ,it doesnt bother me wearing it, however , I would think in todays market there are many better packs available , as someone said the ALICE was a tactical pack , but now adays there packs for every purpose , specialty packs . I would examine what your needs are before you buy , for instance is this a secondary Bug Out bag? It wouldnt be a very good first bugout because of its bulk. If its for hiking I would re asses your needs , ALICE packs generally are not a good choice for hiking , they break your back , I think the form fitting bags that even the weight to your hips is the way to go , you want the energy evenly distributed , I think a pack is narrow at the top and bulk at the bottom is better , I also prefer a belt at the waist , and on the straps as well to cinch while hiking , just my preferance.
Dont concern yourself with carry bulk ammo , unless your in the need it would be highly advisable to dig a hole and waterproof a container and we call this a cache , strategically located along the trail you intent to take (before hand) that way you can take limited amount of ammo ,the ammo will weigh a bag down in a hurry , have a good belt to carry canteens , not getting too off the OP but having a cache pre-planned is an excellent idea to lesson the pack load , these caches can have an assortment of things from food /water/ammo/tools/weapons/clothing/etc ,