The way the guy on the left is carrying the AK is how we carry our primary weapons in combat in the IDF. It's good because u can leave it hanging there for fast pulling when u use ur hands or do a long walk to the objective.
As for ammo pouches, you can make self-made vests with as many pouches you can place, and make them as big as you want... For example, some vests have 2 pouches of 3 mags each (medic vests and m203 vests). Also I heard some places are making customized sniper vests since snipers don't need many magazine pouches but need a comfortable way to carry their sniper ammunition and sniper rifle.
As for backpack, in Israel, for example, we carry the M24 in a special backpack designed to keep it from losing zeroing until you reach your position (until then you walk with your primary weapon (usually m16 type) the standard way in case something goes wrong on the way). Some also carry it like the guy on the right carries his M-16, but on the right shoulder. However, this is rare as you don't need it accessible during movement and it may hit something and lose zeroing.
As for ammo pouches, you can make self-made vests with as many pouches you can place, and make them as big as you want... For example, some vests have 2 pouches of 3 mags each (medic vests and m203 vests). Also I heard some places are making customized sniper vests since snipers don't need many magazine pouches but need a comfortable way to carry their sniper ammunition and sniper rifle.
As for backpack, in Israel, for example, we carry the M24 in a special backpack designed to keep it from losing zeroing until you reach your position (until then you walk with your primary weapon (usually m16 type) the standard way in case something goes wrong on the way). Some also carry it like the guy on the right carries his M-16, but on the right shoulder. However, this is rare as you don't need it accessible during movement and it may hit something and lose zeroing.