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Overview[]

Weapon mods can be built from raw materials and attached to weapons at weapons workbenches. There are over 700 mods,[1] generally including sights, barrels, stocks, receivers, magazines and more. The Gun Nut perk is required to create better modifications for guns. The Science! perk is used to create better modifications for energy weapons and create advanced modifications for bullet based firearms. The Blacksmith perk is used to create better modifications for melee weapons.

Perks and weapon mods[]

Most firearms, including energy weapons, offer the option to customize the grip/stock, receiver and sight, changing which perks affect the weapon.

  • A firearm with an automatic receiver gets bonuses from the Commando perk.
  • A firearm with a non-automatic receiver and pistol grip get bonuses from the Gunslinger perk.
  • A firearm with a non-automatic receiver and a stock mod get bonuses from the Rifleman perk.
  • The Sniper perk only works with a non-automatic firearm with a scope, which uses the "hold breath" mechanic.

Grip mods create pistol weapons, while stock mods create rifle weapons. This allows for almost any ranged firearm to be customized to fit the player's character build.

Action Points and weapon mods[]

This section is based on research presented in YouTuber RedMage's [1] video: "Fallout 4: VATS and AP Formula Solved!"10mm pistol

The formula[]

Attacking from V.A.T.S. uses up Action Points (AP). There are three numbers that determine what the AP cost is for every type of modded weapon: the weapon's base AP cost, the weapon's AP multiplier, and the mod's AP effect, and they do it based on this formula:

weapon base AP cost + (weapon AP multiplier x mod AP effect)

Each weapon has a different base value of action points that it uses per shot. For instance, a 10mm bare receiver costs 21 AP per shot in V.A.T.S., so its AP base value is 21.

Each type of weapon also has an AP multiplier that determines how much effect mods have on the AP of that type of weapon. Combat shotguns, for instance, have an AP multiplier of 1.75, while laser guns have an AP multiplier of 1.25, meaning mods applied to combat shotguns will have a greater impact on AP (up or down) than mods on laser guns.

Finally, each mod has an AP effect, which is how strongly it changes the weapon's AP cost. There are some general patterns to how strongly the mods affect all gun types, but it's inconsistent. For instance, the reflex sight has a consistent -3 effect on all gun types tested, but the long barrel mod has an effect of +1 on 10mm pistols, but +4 on hunting rifles.

Weapon and mod details[]

Known weapon stats
Type Base AP cost AP multiplier
10mm pistol 21 1.4
Combat shotgun 31.5 1.75
Hunting rifle 25.2 1.4
Combat rifle 22.5 1.25
Laser gun 21 1.25
Example

A combat rifle (base AP cost = 22.5; AP multiplier = 1.25) with reflex sight (AP effect = -3):

22.5 + (1.25 x -3) = 18.75 AP cost per shot
10mm Receiver Mods AP Cost Multiple Step Values
  • Basic: 21 (0: default)
  • Light: 14 (-5)
  • Heavy: 28 (+5)
  • Calibrated: 21 (0)
  • Hardened: 21 (0)
  • Auto: 28 (+5)
  • AP Auto: 28 (+5)
  • Hair Trigger: 18.5 (-2)
  • Powerful: 21 (0)
  • Hardened Auto: 28 (+5)
  • Rapid Auto: 28 (+5)
  • Calibrated Powerful: 21 (0)
  • Hardened Piercing Auto: 30.8 (+7)
  • Advanced: 18.2 (-2)
  • Powerful Auto: 28 (+5)
Barrel Mods AP Cost Multiple Step Values
  • Short: 21 (0: default)
  • Long: 22.4 (+1)
  • Long Light: 28 (+0)
  • Long Ported: 22.4 (+1)
  • Long Light Ported: 21 (0)
Grip Mods AP Cost Multiple Step Values
  • Standard: 21 (0)
  • Comfort: 21 (0)
  • Sharpshooter: 19.6 (-1)
Magazine Mods AP Cost Multiple Step Values
  • Standard: 21 (0)
  • Large: 23.8 (+2)
  • Quick Eject: 19.6 (-1)
  • Large Quick Eject: 21 (0)

Ballistic weapons[]

Slot Mod 10mm pistol Assault rifle Combat rifle Hunting rifle Pipe
pistol/rifle revolver bolt-action
Receiver Standard receiver 001A8A43 001A8A4C 001A8A53 0015E93B 001A8A96 001A8A9A 001A8A90
Light frame receiver 0015BD70 0018895B 00185BEB 00155036 0015C856 0015C89A 0015C87B
Heavy frame receiver 0015BD6F 0018895A 00185BEA 00155035 0015C855 0015C899 0015C87A
Calibrated receiver 0015BD6D 00188958 00185BE8 00155033 0015C853 0015C897 0015C878
Hardened receiver 0015E92A 0018895C 00185BEC 00155037 0015C857 0015C89B 0015C87C
Automatic receiver 0015E928 00188952 00185BE2 0015C84B
Armor piercing automatic receiver 0015BD6A 00188953 00185BE3 0015C84C
Hair trigger receiver 0015BD6E 00188959 00185BE9 0015C854
Powerful receiver 0015E92B 0018895D 00185BED 00155038 0015C858 0015C89C 0015C87D
Hardened automatic receiver 0015FA2C 00188954 00185BE4 0015FA2D
Rapid automatic receiver 0015BD69 00188955 00185BE5 0015C84F
Calibrated powerful receiver 00161D09 0018895E 00185BEE 00161D0C 00161D0D 001916B9 001916AC
Hardened piercing auto receiver 00161D19 00188956 00185BE6 00161D1C
Advanced receiver 0015BD67 00188951
Powerful automatic receiver 0015FA31 00188957 00185BE7 0015C852
Tuned receiver 00155034 0015C898 0015C879
.45 receiver Standard 0015C849 Standard
.38 receiver 00210488 0021048A Standard 0021048E 0021048C
.308 receiver 00185BE1 Standard 0015C895 Standard
.50 receiver 00155031 0015C876
Barrel Stub barrel 001A8A92 001A8A98 001A8A8C
Short barrel 001A8A40 0018894A 00185BFC 001362B0 0015C836 0015C888 0015C863
Short light barrel 000A7684 00185BFD 0015502F 0015C837 0015C889 0015C864
Long barrel 0015BD57 00188948 00185BF9 0015E92E 0015C833 0015C885 0015C860
Long light barrel 0015BD58 00185BFA 0015E92F 0015C834 0015C886 0015C861
Ported barrel 0018894B
Vented barrel 00188949
Short ported barrel 0018894B 00185BFE 001651C4 001651C6 001651C2
Long ported barrel 0015BD5A 00188949 00185BFB 0015E930 001651C3 001651C5 001651C1
Long light ported barrel 0015BD59
Long finned barrel 00027F2E 00027F2F 00027F2D
Grip Standard grip 001A8A41 001A8A93 001A8A99 001A8A8D
Comfort grip 0015E926 0015C838 0015C88A 0015C865
Standard stock 0015C83B 0015C88D 0015C868
Sharpshooter's grip 0015E927 0015C839 0015C88B 0015C866
Short stock 0018894E 00185C02 0015E933
Full stock 0018894C 00185BFF 001362B1
Markman's stock 00185C00 0015E931 0015C83C 0015C88E 0015C869
Recoil compensating stock 0018894D 00185C01 0015C83D 0015C88F 0015C86A
Magazine Standard magazine 001A8A42 0018897A 00185C05 001A8A6B 001A8A94
Medium magazine 001362B5
Large magazine 0015BD60 00185C03 001362B4 0015C840
Quick eject mag 0015BD63 0018897B 001A8A6C 001A8A95
Medium quick eject mag 00185C06 0015E935
Large quick eject magazine 0015BD61 00185C04 0015E934 0015C841
Drum magazine 00188978 0015C83E
Quick eject drum mag 00188979 0015C83F
Sights Standard sights 001A8A44 001A8A4D 001A8A54 0015503D 001A8A97 001A8A9B 001A8A91
Glow sights 0015BD78 00185C08 0015503C 0015C85E 0015C8A2 0015C883
Glow reflex sight 0022BA9E 0022BA9D 0022BA9F
Reflex sight (dot) 0015BD76 00188967 0018004D 0015503B 0015C85D 0015C8A1 0015C882
Reflex sight (circle) 0015BD77 001F425B 00185BF8 00247258
Short scope 00188963 00185BF4 0015E940 0015C85C 0015C8A0 0015C881
Medium scope 00188961 00185BF2 0015E93E 0015C85B 0015C89F 0015C880
Long scope 0018895F 00185BF0 0015E93C 001916B3 001916BA 001916AD
Short night vision scope 00188964 00185BF5 0015E941 001916B6 001916BD 001916B0
Medium night vision scope 00188962 00185BF3 0015E93F 001916B5 001916BC 001916AF
Long night vision scope 00188960 00185BF1 0015E93D 001916B4 001916BB 001916AE
Recon scope 00184C58
Short recon scope 002492D6 002492D7 002492DA 002492DF 002492E0 002492DE
Long recon scope 00188966 00185BF7 0015503A 001916B8 001916BF 001916B2
Muzzle No muzzle
Bayonet 0015E937
Small bayonet 0015C845 0015C891 0015C872
Large bayonet 00185BDC 0015C844 0015C890 0015C871
Compensator 0015BD64 0018894F 00185BDE 0015E938 0015C846 0015C892 0015C873
Muzzle brake 0015BD65 001916A1 00185BDF 0015E939 0015C847 0015C893 0015C874
Suppressor 0015BD66 00188950 00185BE0 0015E93A 0015C848 0015C894 0015C875

Energy weapons[]

Weapon Slot Mod AP Cost Change Description Req Rank Form ID
Laser gun Capacitor Standard capacitor Unchanged Standard. None 0012ECED
Photon exciter unchanged Improved critical shot damage and accuracy. None 001877F1
Beta wave tuner Unchanged Adds burning damage. Improved range. None 001877F2
Boosted capacitor Unchanged Improved damage. Reduced ammo capacity. None 001877F3
Photon agitator Unchanged Superior critical shot damage, accuracy and ammo capacity. Science! 1 001877F4
Gamma wave emitter Unchanged Adds better burning damage. Better range and ammo capacity. Science! 1 001877F8
Maximized capacitor Unchanged Better damage. Science! 2 001877F6
Boosted photon agitator Unchanged Superior critical shot damage and ammo capacity. Better accuracy. Improved damage. Science! 2 001877F7
Boosted gamma wave emitter Unchanged Adds better burning damage. Superior ammo capacity. Better range. Improved damage. Science! 2 001877F8
Overcharged capacitor Unchanged Superior damage. Improved ammo capacity. Science! 3 001877F9
Barrel Short barrel -10% None 0009983D
Long barrel +10% Better range, improved damage, sighted accuracy and recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 1 00091FB5
Automatic barrel +25% Improved rate of fire, range and sighted accuracy. Worse recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 1 000997C9
Sniper barrel +35% Superior damage and range. Worse recoil. Poor ammo capacity and hip-fire accuracy. Science! 00099835
Improved short barrel -10% Better damage. Science! 1 001877E7
Improved long barrel +10% Better damage and range. Improved sighted accuracy and recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 2 001877E6
Improved automatic barrel +25% Superior rate of fire. Improved damage, range and sighted accuracy. Worse recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 2 001877E8
Improved sniper barrel +35% Exceptional damage. Superior range. Worse recoil. Poor ammo capacity and hip-fire accuracy. Science! 2 001877E9
Grip Standard grip -10% Standard. None 00099836
Comfort grip -10% Improved recoil and hip-fire accuracy. None 001877EA
Sharpshooter's grip -15% Better recoil and hip-fire accuracy. Science! 1 001877EB
Short stock Unchanged Exceptional sighted accuracy. Better recoil and aim with scopes. Improved bash. None 00091FB7
Full stock +20% Exceptional sighted accuracy. Better recoil and aim with scopes. Improved bash. Science! 1 00091FB6
Markman's stock +20% Exceptional sighted accuracy. Superior recoil and aim with scopes. Improved bash. Science! 2 001877ED
Recoil compensating stock +20% Exceptional sighted accuracy and recoil. Better aim with scopes. Improved bash. Science! 2 001877EC
Sights Standard sights Unchanged Standard. None 001877FA
Improved sights -5% Improved focus and sighted accuracy. None 001877FB
Short scope +30% Improved magnification. Superior sighted accuracy. None 001877FD
Reflex sight -15% Better focus and sighted accuracy. Science! 1 001877FE
Medium scope +40% Better magnification. Superior sighted accuracy Science! 1 001877FC
Long scope +50% Superior magnification and sighted accuracy. Science! 2 000BDCF8
Short night vision scope +30% Night vision. Improved magnification. Superior sighted accuracy Science! 2 00187801
Medium night vision scope +40% Night vision. Better magnification. Superior sighted accuracy. Science! 2 00187800
Long night vision scope +50% Night vision. Superior magnification and sighted accuracy. Science! 2 001877FF
Short recon scope +30% Tracks targets. Improved magnification. Superior sighted accuracy. Science! 3 002492B4
Long recon scope +50% Tracks targets. Superior magnification and sighted accuracy. Science! 3 00187802
Muzzle No muzzle Unchanged Standard None
Beam splitter Unchanged Splits beam into multiple projectiles covering a wider area. Poor accuracy and range. Science! 1 00020BD1
Beam focuser Unchanged Better range, accuracy, and recoil. Science! 1 000BDCF9
Gyro compensating lens Unchanged Superior recoil. Reduced range. Science! 1 000C38ED
Amplified beam splitter Unchanged Splits beam into multiple projectiles covering a wider area. Reduced accuracy. Poor range. Science! 2 001877F0
Fine-tuned beam focuser Unchanged Superior range and accuracy. Better recoil. Science! 2 001877EF
Quantum gyro compensating lens Unchanged Exceptional recoil. Reduced range. Science! 3 001877EE
Plasma gun Capacitor Standard capacitor Unchanged Standard. None 00100AE6
Beta wave tuner Adds burning damage. Improved range. ? 0019ECC5
Boosted capacitor Improved damage. Reduced ammo capacity. ? 0019ECC6
Photon exciter Improved critical shot damage and accuracy. ? 0019ECC4
Photon agitator Superior critical shot damage. Better accuracy and ammo capacity. Science! 2 0019ECC7
Gamma wave emitter Adds better burning damage. Better range and ammo capacity. Science! 2 0019ECC8
Maximized capacitor Better damage. Science! 2 0019ECC9
Boosted photon agitator Superior critical shot damage and ammo capacity. Better accuracy. Improved damage. Science! 3 0019ECCA
Boosted gamma wave emitter Adds better burning damage. Superior ammo capacity. Better range. Improved damage. Science! 3 0019ECCB
Overcharged capacitor Superior damage. Improved ammo capacity. Science! 4 001A8AAA
Barrel Short barrel -10% Standard. ? 00127792
Splitter Fires multiple projectiles. Improved damage. Poor accuracy. ? 0010D531
Automatic barrel +25% Improved rate of fire, range and sighted accuracy. Worse recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 1 00102B5C
Sniper barrel +35% Superior damage and range. Worse recoil. Poor ammo capacity and hip-fire accuracy. Science! 2 0010B9D6
Flamer barrel 30% Flame-thrower conversion. Science! 2 0005E6D2
Improved short barrel -10% Improved damage. Science! 2 0019ECC0
Improved splitter Fires multiple projectiles. Better damage. Poor accuracy. Science! 3 0019ECC1
Improved automatic barrel Superior rate of fire. Improved damage, range and sighted accuracy. Worse recoil. Reduced ammo capacity. Poor hip-fire accuracy. Science! 3 0019ECC3
Improved sniper barrel Exceptional damage. Superior range. Worse recoil. Poor ammo capacity and hip-fire accuracy. Science! 3 0019ECC2
Grip Standard grip Standard. ? 00100AE7
Comfort grip Improves recoil and hip-fire accuracy. ? 00100AE7
Standard stock Exceptional sighted accuracy. Better recoil and aim with scopes. Improved bash. Science! 2 00111F7C
Markman's stock Exceptional sighted accuracy. Superior recoil and aim with scopes. Improved bash Science! 3 0005E6CF
Recoil compensating stock Exceptional sighted accuracy and recoil. Better aim with scopes. Improved bash. Science! 3 00108038
Sights Standard sights Standard. ? 00188A1A
Short scope Improved magnification. Superior sighted accuracy. ? 001B6363
Reflex sight Better focus and sighted accuracy. Science! 1 00115AB9
Medium scope Better magnification. Superior sighted accuracy Science! 2 001B6361
Long scope Superior magnification and sighted accuracy. Science! 2 001B635F
Short night vision scope Night vision. Improved magnification. Superior sighted accuracy Science! 3 001B6364
Medium night vision scope Night vision. Better magnification. Superior sighted accuracy. Science! 3 001B6362
Long night vision scope Night vision. Superior magnification and sighted accuracy. Science! 3 001B6360
Short recon scope Tracks targets. Improved magnification. Superior sighted accuracy. Science! 4 002492BA
Long recon scope Tracks targets. Superior magnification and sighted accuracy. Science! 4 001357CF
Gamma gun Barrel Standard dish Standard. ? 0014F6E6
Deep dish Better range and damage. Science! 4 0014F6E7
Grip Standard grip Standard. ? 001889D3
Sharpshooter's grip Better recoil and hip-fire accuracy. Gun Nut 2 0014F6E8
Muzzle
Electric signal carrier antennae Hold fire to charge additional electrical damage. Science! 3 0014F6EA
Signal repeater Improved rate of fire. Science! 4 0014F6E9

Melee weapons[]

Weapon Slot Mod Description Req Rank Form ID
Baseball bat Upgrade Barbed wire Armor piercing. Improved damage. None 00182CD1
Nails Armor piercing. Better damage. None 00182CCF
Razors Targets bleed. Better damage. None 00182CD0
Chain-wrapped Superior damage. Blacksmith 1 00182CD4
Saw blades Targets bleed. Exceptional damage. Blacksmith 2 00182CD3
Material Black No effect None 001A034B
Blue No effect None 001A034C
Cedar No effect None 001A0350
Grey No effect None 001A034D
Mahogany No effect None 001A034F
Oak No effect None 001A0351
Aluminum Increased Damage Blacksmith 1 001A001D
Chinese officer sword
Combat knife
Machete
Revolutionary sword
Switchblade
Upgrade Serrated blade Increased Damage Blacksmith 2 00187851

Other[]

Weapon Slot Mod Description Req Rank Form ID
Junk Jet Receiver JunkJet receiver Standard. None 00111FFA
Barrel Short barrel Standard. None 0016048E
Long barrel Superior range and sighted accuracy. Better recoil. Poor hip-fire accuracy. Gun Nut 1 00102D57
Grip Standard stock Standard. ? 0016048F
Recoil compensating stock Exceptional recoil. ? 00160490
Sights Standard sights Standard. ? 0023A554
Gunner sight Better focus and sighted accuracy ? 00160491
Muzzle
Electrification module Adds electrical damage to projectiles. Gun Nut 2 00102D59
Ignition module Adds fire damage to projectiles. Gun Nut 3 Science! 1 00102D58

Notes[]

  • Each time a new mod is built, the Sole Survivor receives a small amount of XP.
  • Building weapon mods replaces the current mod applied to the weapon, and the replaced weapon mod is stored in the character's inventory. Attempting to craft a weapon mod which is already present in the character's inventory will apply the mod from the character's inventory instead of building a new mod.
  • Mods stored in a workshop can be reused, and they will be available at all other settlements connected by a supply line. Mods can also be stored in containers.
  • Every disassembled weapon mod has a weight of 0.5.
  • Mods purchased from merchants may be reused an unlimited amount of times on as many suitable weapons as one wishes. The breakdown resource value for the weapon will reflect the addition of the mod.
  • Codsworth and Paladin Danse will love it when the player character creates weapon mods, and Preston Garvey likes it.
  • Unlike armor modifications, most weapon mods cannot simply be removed from a weapon except for muzzle modifications. They must be replaced with an available or a newly created modification before the desired mod will be put into the Sole Survivor's inventory. Should the Sole Survivor not have the skill or resources to create the higher tier mods, the mod on an acquired weapon may be replaced with standard mods with fewer resources expended and no skills required.
  • Each mod may have up to eight qualities describing the magnitude of the mod's effect on weapon stats. These qualities are always sorted in descending order in the mod's description, ranging from big bonus to big penalty: Exceptional > Superior > Better > Improved > (Standard) > Worse > Reduced > Inferior > Poor
  • The Nuka-World add-on includes new melee weapon mods that include rockets (like the super sledge) along with weighted and heating coil mods.
  • The mod reference will not work to attach mods to weapons using the console. "help suppressor 4 omod" can be used to see a list of item references which can be used to mod weapons in the console. However, the help information does not include which type of weapon it belongs to. This applies to both the "amod" and "attachmodtoinventoryitem" methods of adding the mod to the item. It is still possible to use a trial-and-error method to document the item type with the mod reference from the help result. [citation needed]

References[]

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