I know you can change the rarity, but I'm not too sure thats what I'm looking for. I just want to prevent more than 1-2 guns spawning in same crate.

I dont think there is a way to do that, even with rarity set or amount set to be spawned it only allows you to choose each individual weapon and not the probability for each of those items to be spawned in the same crate, When you have so many weapons the chances of them spawning in the same crate increases,

Merged post

When you look at it , I have 4232 containers which would give you one chance in 248 of getting one particular weapon in any single crate (not taking away oil/food/car part containers= too lazy)  , The dev would have to change the coding to look for any of the 17 weapons in each container before putting in another one , maybe slow down the server depending on crate respawn/destroy/looted rate ?

One way to do it would be to scan every container & remove the items.
wait for a crate spawn , wait 1-2 seconds for items to be finalised, then loop round the contained items,
put a hashed short name into a table on a colision remove the current item.

I know for a fact you can do it via a stacking plugin., but you still need to scan & adjust...
.... also you would have to ensure it does not screw with the game mechanics for non player items.
I use a different method for my stacking plugin... since i have to destinguish between users putting shit into a stoarge crates and other self generated crates.
as regards impact... not really... if the code is good.
It's  gonna cost for a custom plugin I think...

I can see that will be fun scanning 4232 containers and adjusting the contents which are randomly chosen from all available items in loot list.