This is the "Equipment Weapon" template.
It should be called in the following format:
{{Equipment Weapon |Damage= |Hands= |WeaponRange= |Reload= |WeaponCategory= |WeaponGroup= |Ammunition= }}
Edit the page to see the template text.
This template defines the table "Equipment_Weapon". View table. This template adds rows to the table "Equipment", which is declared by the template Equipment Item. View table.