First off, the mechanics that this mod adds are excellent, and it's great that you have a lot of sandbox option customisation. However, in MP, the mod is potentially lethal to server performance.

I run a top 5 server with hundreds of active players - we added this mod today and immediately the server performance significantly degraded to the point we were getting black voids stopping people from moving around. I checked our logs and, effectively, we were DDOSing our own server by shooting our guns. The ATY_shotsfx.true call was firing thousands of times an hour, and was triggered by a player shooting their firearm. This was highly correlated with the server getting overwhelmed and entering a "Busy" state, which causes a whole range of issues including disconnects, desyncs, preventing players from logging in, and black voids.

This mod will absolutely work well on a small server of 10-20 people, but on anything larger with a higher amount of zombies (and therefore more shooting) it is highly likely that it will cause problems.

I'm not sure if there's any way for you to shift things away from the server side and on to the client side, but that would significantly mitigate any problems. We will keep it on our server for another short while to see how it plays out but as it is we will probably remove it.

Great mod, unfortunate about the server performance impact!