Weapon Stats: Roughly the same, but allowing for mods.
Base Damage: Add this number to your die roll to determine measure of success.
Range: A level, which will match a range on the Tiered Effects page. The maximum range you can shoot before taking a penalty to your roll.
Weapon Mods:
6 slots: Stock, Receiver, Barrel, Muzzle, Scope, Magazine
Each slot has certain attributes that can be modified. Custom mods can be manufactured for higher bonuses or to modify multiple attributes.
Stock - Self explanatory. Its going to be literally folding/light/heavy.
Reciever - How hard you pewpew Barrel - Power/Agility(changing weapons, moving it around, CQC shit.) Muzzle - Silenced/Flash Suppressed or not? You can suppress flash but not silence Scope - Self Explanatory? Magazine/Ammunition: Magazine for shit like magpulls, extended, etc.