As it is, all your stuff in your backpack/pants/jacket etc will take damage if shot ONCE. It should be a random number of items that take damage instead since a single bullet is unlikely to turn into a magic bullet that turns around and bounces from object to object damaging all. The amount of items damaged should be depending on the weapon type as well i.e. a lot of damaged items with shotguns, few with a pistol, some more with a rifle (piercing through multiple items etc etc).
Water canteens and bottles should also lose water content if they are within the randomly selected items taking damage. And the amount of water you can refill them with should also be re-adjusted to the percentage that is randomly selected (i.e. let say a full water canteen gets shot and randomly loses 60% of its water content - then you can only refill it to 40% because the bullet-hole leaks the rest if the canteen is not patched up).