Gunsmith's Workbench
From HellWiki
A gunsmith workbench allows you to make guns, their components and ammo. It is highly valued among crafters as gun recipes give tons of XP. However, materials are also hard to come by, so unless you got someone to supply you, have a fair amount of scavenging skill or is willing to spend tons of money in parts, you should probably not waste your time with gunsmithing.
Gunsmithing recipes use (mostly) pistols and rifles (depending on what gun you want to create) skill along with crafting skill. The best guns can only be aquired through crafting, so gunsmiths are aways in high demand.
Help needed