If the name of a modification is prefixed with a number in between parentheses, it means it's a combination of multiple conversions. The number denotes the number of "steps" performed (mods combined) to form this.
=== Universal modifications ===
This list details services that are generally applicable to any firearm (including [[Customs:Major|Major Customs]] creations).
==== Barrel threading ====
The barrel threading service is available to allow a firearm to accept certain muzzle devices. A weapon receiving this service does not get a special name or nomenclature, but becomes compatible with '''Standard muzzle devices'''.
Barrel threading costs [[File:Parallar symbol.png|10px]]'''100''', and is available to all firearms chambered in pistol, rifle, or shotgun calibers '''EXCEPT''' the following:
* Weapons already compatible with any type of muzzle devices (Standard, AK, MAC, MP5 3-lug, MP9)
* Weapons with integrated muzzle devices
* Revolvers (except the [[Tula Arms Nagant M1895]], which CAN be threaded)
* Specific weapons:
* [[Golden Gun]]
* [[Joshua]]
* [[Pen gun]]
==== Durability upgrades ====
Firearms chambered in a pistol, rifle, or shotgun caliber can receive upgrades to the barrel, bolt (when applicable), and other critical pressure-bearing parts, in the form of harder metals and protective coatings. These upgrades are referred to as '''durability''' upgrades.
To receive a durability upgrade, the donor weapon's Condition must be 100.00%. If a firearm with a durability upgrade is rechambered or receives any type of barrel modification, the upgrade will be preserved.
The following weapons CANNOT receive durability upgrades:
* [[Golden Gun]]
* [[Joshua]] (considered to already have the '''S7 TiN''' upgrade, which cannot be replaced with a different upgrade)
* [[Pen gun]]
{| class="wikitable sortable" style="font-size:10pt"
|-
! Upgrade name !! Effects !! Cost (in [[File:Parallar symbol.png|10px]]) !! Description
|-
| '''Original parts''' || None || '''500''' || Restores the weapon to its factory original state, reinstalling the original barrel and pressure-bearing parts
|-
| '''S7 tool steel''' || Maximum Condition '''x1.25''' || '''1000''' || Replaces the barrel and certain pressure-bearing parts with equivalents made of ultra-durable S7 tool steel.
|-
| '''S7 steel + Titanium Nitride coating (S7 TiN)''' || Maximum Condition '''x1.5''' || '''2000''' || The S7 steel parts are coated in a gold-colored Titanium Nitride protective finish, increasing hardness and further extending the weapon's durability.
|-
| '''S7 steel + NP3 coating (S7 NP3)''' || Maximum Condition '''x1.25'''<br/>Condition restored by [[Crafting items#Toolkits|Gun Cleaning Kits]] is '''doubled''' || '''2000''' || The S7 steel parts are coated in a silver-colored nickel-boron NP3 protective finish, improving lubricity and making the weapon much easier to clean.
|}
=== Class 1 weapons ===
{| class="wikitable sortable" style="font-size:9pt"
|-
! Weapon !! Mods available !! Pricing Cost (in [[File:Parallar symbol.png|10px]])
|-
| [[Accuracy International AWSM]] || L115A3 LRR || '''200'''