Level one and level two are cleaning and maintaining your weapon along with installation and adjustment of sight. Levels three through six gain repairs and customization (3=easy, 4=average, 5=difficult, 6=very difficult, etc). Level six you can make any weapon you have the specifications for, and the tools. (auto lathe – 50,000 eb, Full Master Weaponsmith Tool Set – 10,000 eb, a +1 kit is 4x for both, and a +2 kit is 10x for both). Level seven, you can make a new gun that uses NO new technological breakthroughs, but the weapon should be put through an in-game prototype series testing. Level eight and above, you can tweak the rules a little bit, and you must definitely put the concept through an in-game prototype series testing. The GMs must approve any new weapon, and “tweaking” process.
A (simple) tool kit is required to change a scope or install a sling. A Weaponsmith Tool Kit (1000eb) is required to make any repair or modification that is Easy or Average. A Full Master Weaponsmith Tool Set is required for any repair or modification that is Difficult and above. A metal lathe (and proper tools and dies) is required for any thing to do with a barrel or similar thing including threading (and usually building) a silencer.