The following weapons CANNOT receive durability upgrades:
* [[Golden Gun]]
* [[Joshua]] (considered to already have the '''S7 PH TiN''' upgrade, which cannot be replaced with a different upgrade)
* [[Pen gun]]
| '''Original parts''' || None || '''500''' || Restores the weapon to its factory original state, reinstalling the original barrel and pressure-bearing parts
|-
| '''S7 tool steel17-4 PH Stainless Steel (PH)''' || Maximum Condition '''x1.25''' || '''1000''' || Replaces the barrel and certain pressure-bearing parts with equivalents made of ultra-durable S7 tool 17-4 PH martensitic stainless steel.
|-
| '''S7 steel 17-4 PH SS + Titanium Nitride coating (S7 PH TiN)''' || Maximum Condition '''x1.5''' || '''2000''' || The S7 steel 17-4 PH parts are coated in a gold-colored Titanium Nitride protective finish, increasing hardness and further extending the weapon's durability.
|-
| '''S7 steel 17-4 PH SS + NP3 coating (S7 PH NP3)''' || Maximum Condition '''x1.25'''<br/>Condition restored by [[Crafting items#Toolkits|Gun Cleaning Kits]] is '''doubled''' || '''2000''' || The S7 steel 17-4 PH parts are coated in a silver-colored nickel-boron NP3 protective finish, improving lubricity and making the weapon much easier to clean.
|}