Maybe if ammunition spawns were reduced and there was a chance for ammunition to spawn when a gun spawns then it would be more like “I’ll never use any of these, but I will cart them all home because I am obsessive that way.” and more like “Oh, pistol and a couple of spare clips, I can’t use it forever, but will grab it in case I get into trouble on my way home…” which would seem like more fun, if less realistic. Although the difficulty of actually predicting what the aftermath of mass panic, looting, then occasional scavenging would do to a place makes realism a little more difficult than one might expect.
Military forces on the other hand should be universally equipped with advanced weapons, practical side-arms, and high quality armour. But either leave a trail of spent casings, discarded gear, plentiful corpses, and their gear’s condition should be consistent with having been chased, ambushed, and mauled. Or it should be guarded by whatever killed them too quickly to deplete their supplies, or whatever they transformed into…