50 weapon with unique bullets, properties, logic and drawing routines? Even in programming language that'd be hard to maintain. Construct allows to organize objects in "families", you can think about it like a container of all instances of classes included within it (kinda "base class").
Construct eventsheets are based on events rather than scripts, I like actual functionality of it. Before getting into eventing you can prepare a pseudocode.
As for using methods I recommend getting to know "Function Object". It fully includes the idea of making methods with returnable value. Construct documentation describes it.