I certainly don't think the rules are perfect, in their pre-release form. But I also don't know if throwing them out entirely before you've even used them makes a lot of sense, either.
Resupply is not actually hard to come by in this world, unless you make it so. My group started out pretty low on ammo, and also throwing ammo dice left and right. Ran low quickly, adapted to using minimal ammo dice in most situations, except in some roleplay-related situations... but also scavenged what they could from the group they encountered. Two encounters later and the support of a local commander and they have a few hundred rounds of 5.45, 7.62, a grenade or two each, and a couple of RPGs. All of this just from picking what they can off of remains -- and it's not like there was a lot there either. So far everyone they've faced has had 2 or 3 mags, max. But hey if you drop a few guys like that quickly, or convince them to surrender, it adds up. My group is currently not worried about ammo (aside from one or two specialty weapons they'd like to use, like the SVD), and have moved on to other worries instead.