You probably need to use instance variables (variables specific to the object) in order to make different "stats" for your weapons.
You can then make ONE event that references the instance variables (which can be different per weapon). Global variables aren't as flexible for this type of thing, unless you have a tonne of them - instance variables are much easier to use on item specific stuff. You can easily have all sorts of instance variables, like "reload speed" and "accuracy" or even "weight" - things like that.
Hope this helps.