I think it would be a cool type of perk if you could somehow gain the ability to acquire a larger maximum ammo. Not like extended mag, but your reserve ammo, like the M1911 has 8 shots per mag and 80 extra, what if a perk could double your reserves so if you get a max ammo you could hold 160 extra ammo. This would be more helpful in the later rounds when you have over 10,000 useless points after you have all your perks/weapons.
Another idea which isn't that great, just off the top of my head would be to max your ammo clip by taking all of your reserve ammo and putting it all into one clip. For example, the M1911 would get 88 shots in one clip with no reserve ammo instead of 8 shots and 80 reserve.
