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. There are some general patterns to how strongly the mods affect all gun types, but it's inconsistent. 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.įinally, each mod has an AP effect, which is how strongly it changes the weapon's AP cost. For instance, a 10mm bare receiver costs 21 AP per shot in V.A.T.S., so its AP base value is 21.Įach type of weapon also has an AP multiplier that determines how much effect mods have on the AP of that type of weapon. Weapon base AP cost + (weapon AP multiplier x mod AP effect)Įach weapon has a different base value of action points that it uses per shot.

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: This section is based on research presented in YouTuber RedMage's video: 'Fallout 4: VATS and AP Formula Solved!' 10mm pistol The formulaĪttacking from V.A.T.S. This allows for almost any ranged firearm to be customized to fit the player's character build. Grip mods create pistol weapons, while stock mods create rifle weapons.

The Sniper perk only works with a non-automatic firearm with a scope, which uses the 'hold breath' mechanic.

A firearm with a non-automatic receiver and a stock mod get bonuses from the Rifleman perk.

A firearm with a non-automatic receiver and pistol grip get bonuses from the Gunslinger perk.

A firearm with an automatic receiver gets bonuses from the Commando perk.

Most firearms, including energy weapons, offer the option to customize the grip/stock, receiver and sight, changing which perks affect the weapon. The Blacksmith perk is used to create better modifications for melee weapons. The Science! perk is used to create better modifications for energy weapons and create advanced modifications for bullet based firearms.

The Gun Nut perk is required to create better modifications for guns. There are over 700 mods, generally including sights, barrels, stocks, receivers, magazines and more. Weapon mods can be built from raw materials and attached to weapons at weapons workbenches.

Fallout 4 free mods