|For the full list of mods in Fallout: New Vegas, see Fallout: New Vegas weapon mods.|
Weapon mods, while they have appeared in one way or another in Fallout, Fallout 2, and Fallout 3, they appear as an active feature for the first time in Fallout: New Vegas due to their popularity as a 3rd party mod in Fallout 3. In Fallout 4 weapon modding was significantly expanded, and rather than individual mods for weapons, weapons themselves can be entirely customized with a variety of components.
In Fallout 2, you can pay a mechanic to upgrade certain weapons for you.
List of available weapons
- Desert Eagle .44 → Desert Eagle (exp. mag.)
- .44 Magnum revolver → .44 Magnum (speed load)
- AK-112 assault rifle → Assault rifle (exp. mag.)
- Colt Rangemaster hunting rifle → Scoped hunting rifle
- FN FAL → FN FAL (night sight)
- Wattz 1000 laser pistol → Magneto-laser pistol
- Wattz 2000 laser rifle → Laser rifle (ext. cap.)
- Glock 86 plasma pistol → Plasma pistol (ext. cap.)
- Winchester P94 plasma rifle → Turbo plasma rifle
- Flamer → Improved flamer
- "Big Frigger" power fist → Mega power fist
- Cattle Prod → Super cattle prod
List of merchants
- Valerie, in Vault City
- Skeeter, in Gecko
- Eldridge, in New Reno
- Algernon, in the basement of New Reno Arms. Works for free.
The only upgrades seen in Fallout 3 are scopes, the occasional use of silencers, and the use of extended magazines. Other differences between unique weapons do not technically count as weapon mods, seeing as there is only one of each unique weapon.
Fallout: New Vegas
One of the features added to New Vegas is the ability to custom modify certain base weapons. While in Fallout 3 this was limited to the creation of custom weapons, New Vegas takes this a step further by allowing the creation of weapon variants based on basic weapons by adding weapon mods.
Unique weapons cannot be equipped with weapon mods, with the exceptions of the weathered 10mm pistol, Mercenary's grenade rifle, holorifle, and Elijah's Advanced LAER. While unique guns usually have better base stats, Obsidian Entertainment introduced this inherent drawback of unique weapons to balance out unique and normal weapons and make the choice less of an obvious decision and more of a preference. However, some unique variants have both mods and better base stats, such is the case of the varmint rifle's unique variant, the Ratslayer, which has all of the mods the varmint rifle can be equipped with.
By themselves, the weapon mods serve no function but, once attached to their specified weapon, will change the characteristics, look and/or function to create a distinct variant. The weapon mods range from scopes and silencers to extended mags and several in-between. In the case of the varmint rifle and other such weapons there exists more than one different type of modification. While you are not limited in the amount of total mods you can apply to a single weapon, you are limited to one of each type of mod per single weapon and therefore are not able to stack attributes like increased rate of fire.
Once a weapon mod is attached to a weapon it cannot be removed and remains a permanent feature of that weapon, along with its added attribute. However, this could not always be a good thing. For example, extended magazines is almost always beneficial unless the magazine must be reloaded on a shell by shell basis (ex: cowboy repeater), forcing a longer reload, or a scope on the other hand has pros and cons, as it may increase maximum range, but makes it harder to use in close combat situations.
The addition of a mod to a weapon will permanently increase the overall monetary value of that weapon by the value of the mod, even if the weapon is completely broken at the time it is applied.