Degradable weapon parts. all weapons that are found in the game have been fought with to the death or been laying at the mercy of the weather outside so i would suggest that finding a fully funktional weapon should be extremly rare, when you find a gun it would have a fraktured stock, broken/bent barrel or jammed firing mechanism, or broken/worn out firing pin. Say if you found a M4 thats missing a firing pin and you would have found earlyer another M4 that you would have scavenged for intakt parts (one of these parts beeing a firing pin) you would be able to repair the other M4 by installing the missing part, However as it would be extremly hard to get a working gun as it would need you to find multiple weapons of the same kind i propose the following thing: Say you would find a m16 or hk416 instead of a m4, parts are fairly similar but might require a littel tweaking so add a gunsmits building with stationary manuals and workbences and tools(you could see these items moore like movie props to make it feel moore realistick that a random survivor is able to fix military grade weapons or civilian guns) into cities where there player is able to adjust a part to fit into another gun this at the cost of the modded part not beeing as good as a original part, another possibility create a npc that makes these modificatons to the player. Also this would give the player a possibility of creating any gun they would like, ie AK fire mechanism with a svd barrel creating a hybridgun thats accuracy would be greater then that of a ak and its reliability similar of an ak, taking the best parts of both combined weapons, to this weapon you could add a silencer that would be found in different calibers, .22 .9mm 556, etc. then you could find say a bipod from a random loot or another gun and then you would start to have a silenced battlerifle w/snipersight&bipod&silencer with great reliability due to the mechanism of the ak. Also you could make a gun with the caliber 556 (for zombi killin')and make a switch barrel ex: 7,62x54R (for bandit spankin') that goes onto the same weapon stock, then the player would be able to use two kinds of ammunition instead of one and as a single barrel weights less and takes less room then a entire gun it would be moore appealing to carrry around a second barrel that could be switched out. Again this would make it possible to reduce ammunition spawns as you can use moore kinds of ammo.