Shoot Ice w/ Explosives = Ice Breaks, Tank & Infantry Fall In

I get that the support shouldn't have infinite ammo (i.e. not having to grab from the ammo stash manually). But shouldn't supports start off with max ammo since that's how they would prep into battle? Whenever they are out of ammo, they can grab more ammo manually by pressing 3, but it just seems to not make much sense that the one player with an unlimited stash of ammo doesn't think to come into battle with maxed out ammo at the ready.