You need a weapon workbench to craft any mods for weapons.

Advanced Weapon Mod Crafting - Each weapon category and the types of mods you can make for each.Weapon Mod Crafting Basics - How to craft mods, perks needed, and examples of materials.Don't forget to check the Fallout 4 Beginner Tips and Tricks for more guides! This guide will go over everything about crafting weapon mods including: I'm going to describe the mods available for each weapon category and what you need to make them.