Fallout 4 legendary weapon effects

In Fallout 4, legendary weapon effects are special modifications applied to basic weapons that use special prefix modifiers, not obtainable elsewhere. Legendary weapons cannot be scrapped, but can be further modified and traded with vendors. An on-screen notification informs the player that they have picked up a Legendary weapon; in the Pip-Boy's inventory screen, they are marked with a star. 
Unique weapons use the same spawning system, simply spawning a legendary weapon with guaranteed effects, mods, and a name. The player can rename randomly spawned weapons to create weapons that are identical to uniques: For example, a "Relentless .44 pistol" is identical to Kellogg's pistol.
==Location==
Legendary weapons are most commonly found on the bodies of "Legendary" variants of enemies. These enemies spawn at random locations throughout the Commonwealth, the Island and Nuka-World, depending on the difficulty setting, and will almost always have a Legendary piece of equipment in their inventory. Legendary weapons can also be awarded for completing certain quests, and can be found in tribute chests or as rewards from the Nuka-Cade, albeit rarely.
==List of effects==
Legendary weapon effects can be identified in most cases by prefixes, which identify the weapon's unique effects.
Prefix 	Stat 	Form ID	Lootable weapon type(s)	Unique weapons
Assassin's 	Does 50% more damage against humans 	 	All 	PartystarterPint-Sized Slasher knife
Berserker's 	Does more damage the lower the character's Damage Resistance (up to 200% at 0 resistance) and less damage at higher resistance (50% at 81-100 DR, and 25% at 101 or more DR).	 	Melee, Unarmed 	
Blazing 	Blocking has a 25% chance to set attackers on fire for 50 damage. 	 	Melee only 	
Bloodied 	Does more damage the lower the user's health is (5% damage per 5% health lost, up to +95% damage at 5% HP) 	 	Melee, Unarmed 	Survivor's Special
Cavalier's 	Reduces damage by 15% while blocking or sprinting 	 	Melee, Unarmed 	
Charged 	10% chance to deal 100 Electrical damage on a successful block. 	 	Melee 	
Crippling 	50% more limb damage 	 	All 	Eddie's PeaceWastelander's FriendThe Last Minute
Deadeye 	Time slows down for a moment while aiming(cancels all other slow time effects such as Jet) 	 	Ranged weapons 	
Defiant 	The final shot in the magazine deals twice the normal damage 	 	Ranged weapons 	
Duelist's 	25% chance to disarm attackers on a successful block 	 	Melee, Unarmed 	
Enraging 	Critical hits cause target to frenzy 	 	All 	Good Intentions
Explosive 	Bullets explode on impact doing 15 points area-of-effect damage 	 	Ballistic weapons 	Spray n' PrayKiloton radium rifle
Exterminator's 	Does 50% more damage against mirelurks and bugs 	 	All 	Reba II
Freezing 	Does 10 points cryo damage and will freeze targets on critical hits 	 	All 	
Frigid 	20% chance to freeze the enemy when blockng attacks 	 	Melee, Unarmed 	
Furious 	Damage increased by 15% after each consecutive hit on the same target 	 	Melee, Unarmed 	The Problem Solver Splattercannon Furious power fist
Ghoul slayer's 	Does 50% more damage against ghouls(no effect with Gamma gun) 	 	All 	
Hitman's 	Does 10% more damage when looking down the sights 	 	Ranged Weapons 	
Hunter's 	Does 50% more damage against animals 	 	All 	
Incendiary 	Sets target on fire for 15 damage over 3 seconds (5/second). 	 	Ballistic weapons 	AshmakerThe Gainer
Instigating 	Does double damage if the target is at full health 	 	All 	Old FaithfulSentinel's PlasmacasterAdmiral's Friend
Irradiated 	Does 50 points additional radiation damage 	 	All 	
Junkie's 	Does 15% more damage for each addiction the Sole Survivor has(+180% dmg with 11 chem addictions, and 1 alcohol addiction) 	 	All 	
Kneecapper 	20% chance to cripple all of the target's legs. 	 	All 	Big JimSergeant Ash
Lucky 	Critical shots do double damage and the critical meter fills 15% faster 	 	All 	Righteous AuthorityHub's Alien Blaster
Medic's 	Heals target instead of hurting them 	 	Unused/Mods Only 	
Mutant Slayer's 	Does 50% more damage against super mutants 	 	All 	Virgil's rifle
Never Ending 	Sets ammo capacity equal to the amount one is carrying(excludes laser musket, syringer, harpoon gun and junk jet) 	 	Guns 	Prototype UP77 "Limitless Potential"Wazer WifleAeternus
Nimble 	Provides 75% faster movement while aiming 	 	Guns 	Death From Above
Nocturnal 	Does increasing amounts of damage as the night grows longer and less damage during the day 	 	All 	
Penetrating 	Ignores 30% of the target's Damage and Energy Resistance(Due to a bug, this does not affect Energy Resistance) 	 	All 	Radical Conversion Fencebuster Defender's Harpoon Gun Sword of Wonders
Plasma Infused 	Adds 10 points of energy damage and can turn enemies into goo 	 	Ballistic weapons 	
Poisoner's 	Target is poisoned for 10 seconds (3 points poison damage per second). 	 	All 	
Powerful / Mighty	Provides 25% more damage 	 	All 	
Quickdraw 	Costs 25% fewer Action Points 	 	All 	
Rapid 	25% faster fire rate, 15% faster reload 	 	Ranged weapons 	Experiment 18-AFinal JudgmentProtectron's Gaze
Relentless 	Refills Action Points on a critical hit 	 	All 	Kellogg's pistolButcher's Hook Cito's Shiny Slugger
Resilient 	+150 Damage Resistance while reloading 	 	Ranged Weapons 	Skipper's Last Stand
Resolute 	Slows time momentarily as the last round is chambered 	 	Ranged weapons 	
Sentinel's 	Take 15% less damage while standing and not moving 	 	Melee, Unarmed 	Reckoning
Staggering 	Chance to stagger on hit 	 	All 	JusticeThe Harvester
Stalker's 	If not yet in combat, 100% increased V.A.T.S. accuracy, but costs 50% more AP 	 	Ranged weapons 	Tinker Tom Special
Steadfast 	+50 Damage Resistance while aiming 	 	Ranged Weapons 	
Troubleshooter's 	Does 50% more damage against robots 	 	All 	General Chao's RevengeOutcast Gen-4 10mm pistol
Two Shot 	Fires an additional projectile, but has +25% more recoil 	 	Ranged weapons 	Big BoyOld Reliable Overseer's Guardian
VATS Enhanced 	+33% V.A.T.S. hit chance, 25% less Action Point cost 	 	Ranged weapons 	Deliverer
VATS Enhanced 	40% less Action Point cost 	 	Melee, Unarmed 	Rockville SluggerThe Fish Catcher
Violent 	Deals +25% damage and limb damage, but has +200% more recoil 	 	Ballistic weapons 	Le Fusil Terribles
Wounding 	Targets bleed for 25 points of additional damage, spread over 5 seconds. 	 	All 	Pickman's BladeBloodletter Throatslicer
==Unique weapon effects==
Some effects are not randomly generated legendary weapons. These are known as unique weapon effects, and they can only be found by adding the effect through commands, or getting the unique weapon that they are found on. A removable effect is a weapon mod that is not legendary, i.e. it will block some other mod on the weapon but will not block the legendary mod the game uses to apply legendary effects, allowing the player to move it to a legendary version of the weapon.
Prefix 	Mechanic 	Form ID	Removable	Unique weapons
Atom's Judgement 	+100 Radiation damage. 	 	No 	Atom's Judgement
Automatic 	Automatic fire mode. 	 	No 	Automatic laser musket
Charging 	Irradiates user. Can be charged up to 5 times. 	 	No 	Salvaged Assaultron head
Grognak's Axe 	Hits cause more stagger, and targets take bleed damage. 	 	No 	Grognak's axe (Fallout 4)
Lucky Eddy 	+2 Luck 	 	No 	Lucky Eddy
Lightning 	Fires an electrical charge that arcs between targets. 	 	No 	Tesla rifle
Lorenzo's Artifact Gun	Removes area of effect damage and direct hit radiation poisoning; adds direct hit explosive damage and a push effect.	 	Yes 	Lorenzo's Artifact gun
M4 Carbine 	Lighter weight, changed ammo type to 5.56, +25% fire rate, -15% reload time. 	 	No 	December's Child
Kremvh's Tooth 	Exceptional damage, deals poison and bleeding damage. 	 	Yes 	Kremvh's Tooth
Shem Drowne Sword 	Deals radiation damage. 	 	No 	Shem Drowne sword
Striker 	Shoots modified bowling balls. 	 	Yes 	The Striker
Striker 	50% chance to cripple the target's leg. 	 	No 	The Striker
World Series Logo 	Chance to send targets flying. 	 	No 	2076 World Series baseball bat
Zeta Gun 	Halves area of effect damage and removes direct hit radiation poisoning. 	 	Yes 	Zeta gun
==Detailed explanations==
The legendary weapons and armor that are found on enemies are random; there are certain "pools" of said weapon and armor types specifically tied to the type of enemy and location in which they are spawned. Certain legendary variants of weapons encountered early in the game, such as laser muskets and pipe pistols, will not spawn on Gunners, but will always have a chance to be found on legendary enemies with an area-specific low level cap (e.g. the feral ghouls in Super Duper Mart).
===Berserker===
* The Berserker effect works in reverse as well; having an excessive armor rating will actually decrease the weapon's damage to effectively nothing. The effect is not decreased by Radiation Resistance.
** The "Berserker" mod occasionally causes a miscalculation of damage; the damage decreases if not wearing any base clothing (army fatigues, vault jumpsuit, jeans and t-shirt, etc.).
** The damage calculation is also not shown until the weapon is equipped, and then it will also translate the effect onto other weapons when viewed in the inventory (which is correct; the effect on the equipped weapon will apply the same effect to grenades the player throws.)
** This weapon mod can be added to ranged weapons via console, e.g. "Berserker's Shielded Gauss rifle."
===Cavalier's and Sentinel's===
Because the damage reduction from these effects will stack additively with legendary armor effects that grant a percent damage reduction (including Cavalier's and Sentinel's, as both are also armor effects), due to the fact that they actually add percentage points rather than an actual percent, equipping 7 such pieces that all apply +15% (e.g. Sentinel's on the player character's weapon, both legs, both arms, torso and head) will lead to 100% damage reduction, meaning the character takes no normal damage at all (though exotic effects such as bleeding will still cause damage). This causes enemies to panic and run away, due to how Fallout 4's AI is programmed.
===Crippling and Violent===
*The Crippling effect does not increase a weapon's attack power, but rather its limb damage. Therefore, enemies will still take the same amount of hits to defeat, but their limbs will be easier to cripple.
*Violent will kill a target faster (at the same speed as a Powerful weapon), but the time to cripple a target limb is the same as for Crippling, as the damage increase from it also applies to limb damage; the downside is the increased recoil. As a general rule, Violent is strictly worse than Two Shot.
===Deadeye and Resolute===
* The slow time from the Resolute effect occurs not only when shooting the second to last bullet but also when player character switches to a weapon with the Resolute effect and a single round in the magazine.
* A Resolute laser musket's time slow effect will occur upon the first crank; the player character must wait a short while before resuming cranking or the effect will not activate.
* The slow time effects from Dead Eye and Resolute are not canceled when switching to a different weapon, thus technically allowing the effect to be partially transferred to it. This can be useful to make a better aimed sniper shot.
===Defiant===
* The Defiant effect permanently doubles the damage for any weapon with a capacity of 1, as they are technically always on the "last round" before reloading.
**However, explosive weapons such as the Fat Man see almost no benefit, as the damage multiplier does not apply to explosive damage.
===Explosive===
The Explosive effect is exceptionally powerful when paired with weapons with low base damage per projectile that boasts a high rate of fire or shoots several projectiles, as each projectile will produce an independent explosion, and the flat damage bonus itself is usually more than percentile bonuses.
* The damage dealt by the Explosive prefix is increased by the Demolition Expert perk as well as the Explosives bobblehead. With 4 ranks in Demolition Expert plus the Explosives bobblehead, Explosive weapons actually deal 32.25 explosive splash damage per projectile.
* The area-of-effect damage dealt by the Explosive prefix is also increased by Commando/Gunslinger/Heavy Gunner/Rifleman perks. Rifleman increases damage more than its counterparts due to also decreasing the target's Damage Resistance when resolving the hit.
**Minigun: the best example for the first case. Considering a base damage of 8 points per bullet, adding 15 points of explosive damage to every shot fired effectively triples the weapon's damage output even without taking the splash damage into account, as opposed to the "Mighty" Legendary Mod adding only 25% of 8 which is +2 to an end result of 10 versus 8 + 15 resulting in 23. Installing barrel mods somewhat weakens this effect, but it remains quite powerful regardless. The fact that the splash radius makes the minigun's inherent spread largely irrelevant only serves to further improve the effect's usefulness; as long as the weapon is aimed at the player character's target, it will hit it even if the bullets themselves do not connect.
*** For example, a base minigun does 8 damage per bullet. With Explosive, it does 8+15=23 damage per bullet. With rank 1 of Heavy Gunner, a +20% damage will be achieved, but that bonus is applied to both the original 8 and the explosive 15. It therefore does 1.2 * (8 + 15) = 27 (rounded down) per bullet, instead of just (1.2 * 8) + 15 = 24 damage. At rank 5, it therefore does 2 * (8 + 15) = 46 damage per round, and NOT just (2 * 8) + 15 = 31 damage.
*** The Demolition Expert perk only affects the explosive component. With rank 1, for example, the weapon then does 8 + (1.25 * 15) = 26 damage per bullet. Similarly, maxed out the perk does 8 + (2 * 15) = 38 damage per round.
*** Taken together, this allows the minigun to far exceed its traditional base damage, doing a maximum of 2 * (8 + (2 * 15)) = 76 damage per round, instead of the 46 damage per round as with other weapon classes.
** Shotguns benefit from explosive shots, multiplying their damage output based on the amount of shot/beams in each round fired.
*** An explosive combat shotgun with an advanced receiver (firing 8 projectiles instead of a base of 7), 3 star Demolition Expert and 5 star Rifleman can do up to 2*100+(15*1.75)*8=410 Base Damage per shot. (V.A.T.S. does not take every projectile into account, and the weapon information shown on the Pip-Boy will fall short of the total damage.)
** This effect can only spawn on ballistic weaponry. Laser, explosive and other weapons cannot have this effect without mods or console commands. This is due to various glitches caused by other kinds of weapons.
*** Explosive weapons such as the Broadsider and missile launcher will not work with certain legendary effects, such as Incendiary and Explosive. These effects appear to replace the explosive damage with their own effect, reducing the weapon's damage dramatically.
*** Laser weapons such as the laser rifle appear to function as intended at first as the visual effect functions correctly. However, the actual damage of the explosion greatly increases, instantly killing almost any foe in a single hit. A scatter laser rifle with this effect can outdamage any other weapon in the game. They will also almost always kill the player if they get caught by any recoil damage.
*** Other energy weapons do not function correctly at all, and result in the gun changing its firing animations and sound effects from a laser/plasma/fire-based weapon to a ballistic gun, including a stream of casings being ejected from somewhere behind or inside the weapon.
** When firing Explosive-enhanced weapons in close quarters, their splash damage can injure the shooter just like grenades, missiles or any other explosive munitions do.
** Killing almost any sort of enemy with a powerful Explosive-enhanced automatic weapon in V.A.T.S. will often launch the target dozens of yards into the air and hurl them a considerable distance, especially if one of the salvo's first hits already dealt the killing blow. This can make finding the corpse for looting difficult at times.
** Explosive shots fired from a weapon with this modifier, and unlike shots fired with weapons bearing the Incendiary effect, will not ignite oil pools.
===Freezing and Plasma Infused===
Freezing and Plasma Infused mods are most effective on low base damage weaponry because the amount of damage added is independent of the damage of the gun and adding 10 or 15 to a smaller number has a bigger impact than on a larger one. However, this damage is per attack, not per projectile, so they have little effect with shotguns and energy weapons modded to have the scatter effect.
* The bonus damage from the Freezing and Plasma Infused prefixes scales with all relevant damage modifiers. That is, with 5 ranks in the appropriate damage perk (e.g. Gunslinger for non-automatic pistols,) a Freezing or Plasma-Infused will deal 20 points of bonus energy damage. However, with no ranks in the perk, the gun would only deal the base 10 points of energy damage. This bonus damage is also affected by other perks that modify damage, including Astoundingly Awesome Tales #07, and Lone Wanderer. For melee weapons, the damage is affected by the Rooted perk as well, but does not receive bonus damage from the Strength stat.
** Freezing weapons also have great synergy with critical-focused builds due to their freezing effect on critical hits. With Critical Banker, Four Leaf Clover and a freezing weapon with a low Action Point cost, each instance of combat can be opened by freezing up to 5 combatants (4 without the Far Harbor add-on,) reducing a numbers advantage or allowing free attacks for a time. Use of Overdrive allows this tactic to be used without a V.A.T.S. focused build when paired with a rapid-firing weapon.
*** Certain enemies, such as mirelurks, deathclaws and enemies wearing power armor, cannot be frozen.
** Plasma Infused weapons share many characteristics with "true" plasma weapons, including the latters' high chance of spawning several units of nuclear material on any defeated enemy. Gooifying the target with a critical kill shot virtually guarantees this, thus providing an abundant source for this crafting component, especially for player characters specializing in critical hit chance.
===Furious===
* The Furious effect increases a weapon's damage by 15% after each consecutive hit. That is, hitting an enemy three times in a row will increase the damage of the third hit by 30%. The counter of consecutive hits is reset after not hitting the target for 10 seconds, or after hitting another target. Simply missing a target does not affect the counter, that is, terrain does not count as a target for this effect's definition of "same target," so the player can hit it without resetting the counter.
* The Furious effect does not increase the radiation damage on the radium rifle, only ballistic. This is because the radiation damage is actually an enchantment that is not adjusted by damage modifiers.
===Incendiary, Poisoner's and Wounding===
These effects deal a static amount of damage over time which is not affected by any perk: Incendiary deals deals 3 fire damage per second for 5 seconds (15 total), Poisoner's deals 3 poison damage per second for 10 seconds (30 total), and Wounding deals 5 bleed damage per second for 5 seconds (25 total). In increasing order of utility:
#Poisoner's deals a damage type most targets are immune or highly resistant to, and will in practice do the least of these. In addition, it does not stack with itself, so the faster a weapon shoots, the less noticeable the poison damage will be.
#Incendiary is less resisted, but still enough so that as enemies' levels increase, the added damage will become less and less noticeable. Like Poisoner's, it will also not stack with itself, so slower is better, theoretically.
# Wounding deals damage to which nothing in the game has any immunity or resistance to, and bleed damage also stacks with itself. This means that, for instance, getting hit twice with a Wounding weapon will cause a target to suffer bleed damage twice. Thus, this can be highly lethal on weapons with high rates of fire and/or multiple projectiles per shot (as each projectile Wounds individually), and while damage perks will not affect this, rate of fire perks such as Gun Nut can greatly increase the damage output from Wounding effects.
Wounding is comparable to Explosive in that both deal per-projectile damage even against a single target, which is true of them and only them; Explosive's damage is modifiable by perks, hits multiple targets and is instantaneous, but Wounding ignores all resistances (and the damage modifier from difficulty level).
===Instigating===
* The Instigating mod is at its best when found on powerful semi-automatic or bolt-action weapons, like all kinds of sniper rifles and especially the Gauss rifle. Considering that most, if not all, hostiles will be at full health when the player character is setting up a sniper ambush against an enemy stronghold, automatically dealing double damage against them seriously increases the chance of handing out a chain of one-hit-kills. With a silencer modification, entire locations can be easily cleared with stealth. A fully charged sneak shot from a fully upgraded and silenced Instigating Gauss rifle, coupled with maxed Rifleman, Ninja and Mister Sandman is a virtually guaranteed one-hit-kill against anything that roams the Commonwealth, regardless of distance, difficulty setting and whether or not it was a headshot.
===Irradiated===
* The Irradiated mod is potentially very powerful, scaling extremely well with higher difficulties and higher levels. When combined with the Nuclear Physicist perk, Irradiated weapons do 100 points of radiation damage (10% of max health). At lower levels and difficulties, the normal damage of the weapon may dwarf the 10% max health reduction (due to how radiation damage in Fallout 4 works). Indeed, even at high levels, properly upgraded and geared weapons may also do much better against many enemies. However, high-level human enemies may have over 1,000 health and, due to radiation damage ignoring player damage penalties in higher difficulties, a single irradiated shot could be worth hundreds of damage, highly effective on automatic weapons (even a low-level auto pipe pistol). Irradiated Gamma guns and Radium rifles are even more extreme.
** The Irradiated mod is also very effective against legendary enemies, as it reduces the maximum health points of the target, preventing the healing effect of the mutation.
** Certain enemies exhibit high resistance or even immunity to radiation damage. Ghouls, for instance, are not only immune but are also healed by radiation. Super mutants exhibit a high resistance to radiation, making the effects of the Irradiated mod relatively negligible against them. Furthermore, robots, being non-biological entities, are completely immune to radiation damage. When it comes to other living creatures: as a rule of thumb, if it is affected by the Wasteland Whisperer (Fallout 4), then it is likely also very resistant (or immune) to radiation damage.
===Kneecapper===
* The Kneecapper mod does not increase limb damage in any way; rather, each projectile has a 20% chance to instantly cripple the target's legs.
**This makes the Kneecapper effect most effective on automatic weapons or shotguns, as any single hit will trigger the effect regardless of damage.
**The effect will trigger regardless of where the target is hit.
** The most obvious targets are all types of melee-focused enemies from mole rats or feral ghouls all the way up to deathclaws. A short burst will usually be enough to turn them into sitting ducks, making them unable to close in on their target and therefore depriving them of almost any threat potential.
** While enemies with ranged weapons still pose a threat even with their legs crippled, they collapse to the ground when the effect triggers and remain prone for some seconds, taking them out of the fight temporarily. If that enemy was shooting from behind cover, their line of sight will be broken, thus preventing them from attacking any longer until the Sole Survivor digs them out.
** Kneecapper weapons should not be used to attack flying Vertibirds. When the crippling effect triggers, it will cause a bug by instantly destroying the flyer's turbines while making it impossible to destroy completely. This can be especially aggravating during the quest Rockets' Red Glare for the Railroad, where an attacking Brotherhood of Steel Vertibird must be deestroyed.
*** Kneecapped Vertibirds will hover just above ground level for as long as the player remains in the area. Walking away should trigger their crash into the ground, destroying the Vertibird.
===Lucky===
* Does not stack with the Better Criticals perk.
* Does not actually fill the critical hit meter 15% faster, but rather adds +15% to the per hit gain of the critical hit bar.
===Mighty / Powerful===
* Does not work on the missile launcher.
===Never Ending===
* Powerful weapons that are balanced by reload times, such as the double-barrel shotgun, will have that balance removed; the effect in VATS will be identical to rank 2 of Quick Hands, while outside of VATS the benefit will depend on the reloading time of the weapon. 
* It is not normally possible to find heavy weapons (like the Fat Man or missile launcher) with this effect.
*The Never Ending mod sets ammo capacity equal to the amount one is carrying, eliminating the need to reload. However, this mod can make certain weapons unstable. 
** For example, a laser musket with the effect will consume all ammunition for the gun that is currently in the player's inventory. However, as the musket uses its "energy reservoir" to store the crank charge, and this mod sets the reservoir size to the amount of ammo in the inventory, the mod effectively removes the crank limit. Since the damage of the weapon is based on how many cranks it is given, this gives that single shot a devastating amount of damage. For example, at 200 cranks, a single shot can do about 30,000 damage.
** The Gatling laser has a unique bug relating to this effect. When fired while the player has at least 3 fusion cores, the weapon will seemingly drain most of one core, but will then no longer drain any further energy, resulting in the weapon having infinite ammo. If the player has less than 3 cores, the weapon will instantly drain them. Despite its buggy nature, the unique Gatling laser Aeternus has this effect.
===Nimble===
* The Nimble modifier can be used by players to significantly boost their movement speed while sneaking. Although it can be difficult to walk around with certain weapons sighted (such as weapons with actual scopes), aiming down the sights of a small nimble pistol while sneaking actually results in a faster movement speed than normal (standing) running in power armor.
** The movement speed while overburdened is the same as that while not overburdened, thus, a player can continue moving at running speed while overburdened simply by aiming down a Nimble weapon's sights continuously.
===Nocturnal===
The Nocturnal modifier works in the following way:
* 9:00 AM - 6:00 PM: 33%
* 6:00 - 9:00, AM or PM: 66%
* 9:00 PM - 12:00 AM: 150%
* 12:00 AM - 6:00 AM: 200%
Thus, the "average" multiplier across an entire day (if the player did not simply switch weapons during off-hours) is 97.625%, i.e. a Nocturnal weapon does less "damage per day" than a normal weapon.
===Penetrating===
* The Penetrating mod's effectiveness, due to the exponential curve of armor based damage reduction, does not vary with the target's armor after a certain threshold. When the target's armor rating is less than 15% of the weapon's damage, which is very little, the damage is applied in full (meaning 99%) and the Penetrating effect wasted. If the armor rating is between 15% and 21.4%, a Penetrating weapon will still do full (99%) damage while a standard variant will already experience damage reduction, making the Penetrating weapon increasingly better by comparison (0% to 13.9% more damage). Past this point, which is still very low for semi-automatic weapons, having the Penetrating mod means a static 13.9% increase in effective damage. Since armor penetration becomes more effective the more you have of it, the effective damage increase will be 25.81% if you already have max rank of the Rifleman perk. On a weapon with an armor piercing automatic receiver mod, the effective damage increase will be 34.69%. This is still weaker than a simple mighty / powerful effect, which has an effective damage increase of 35.61% against an armored target.
* When looking at the effect in the Creation Kit, the effect used to determine the percentage of Armor/Energy penetration is the same as the Rifleman perk, which means that unlike what its effect description says, this effect does not ignore the enemy's Energy Resistance.
===Rapid===
* The Rapid mod uses the weapon's base firing rate, so a weapon modded to reduce its firing rate in exchange for more damage, such as a Gatling laser using charging barrels. Due to the way the game calculates bonus percentages, a Gatling laser with the Charging Barrels mod (-83.5% rate of fire) and the Rapid prefix (+25% rate of fire) shoots more than twice as fast as it normally would, at 41.5% of the standard firing rate instead of 16.5%. This effect is essentially what makes the unique Final Judgment variant so deadly. It also largely eliminates the Charging Barrels' greatest drawback (very low rate of fire) and thus makes it far more useful in fights against numerous weak and/or fast-moving enemies that are normally hard to hit, in addition to still inflicting large amounts of damage to anything else as well, no matter how heavily armored it might be.
===Staggering===
* The Staggering prefix, when applied to a weapon with a very high fire rate (such as a ripper or flamer) or with multiple projectiles (such as a combat shotgun), will usually render the target helpless while being hit, reducing the toughest enemies to easy targets. This is especially effective when combined with other effects that can cause stagger, such as Commando or the knockdown effect of Sniper.
* Based on stats from the Creation Kit, non-automatic weapons have a 30% to stagger a target each hit, while automatic weapons have 5%. One-hand or two-hand melee weapons have 50%, which allows weapons like The Harvester to stunlock an opponent.
* Some enemies are immune to stagger (e.g. turrets). Also, it may not be possible to stagger some enemies under certain circumstances (e.g. super mutants and regular humans/ghouls that are executing unarmed attacks).
===Two Shot===
* The Two Shot modifier makes the weapon fire an additional projectile while still using only 1 ammo and at slightly reduced accuracy and can greatly increase recoil. The game adds the base (i.e. unmodded) damage of the gun to its current (modded) damage and then splits the combined damage evenly into two projectiles. For example, an unmodded hunting rifle does 37 damage, while a .50 cal hunting rifle does 64. So a Two-shot .50 cal hunting rifle does 64+37 = 101 damage, resulting in two projectiles hitting for 50.5 each. The damage value displayed in the Pip-Boy is the damage of both projectiles combined.
** It is not normally possible to find heavy weapons like the missile launcher or harpoon gun with this effect.
** The game uses the combined damage to calculate the damage reduction multiplier of the target's armor, so when both bullets hit, it does the same damage that one bullet with the combined damage would do. Therefore a Two Shot weapon will do more damage than the shots of an identically modded normal weapon and its unmodded variant combined.
** As only the weapon's base damage is added, a shot from a heavily modded version of a two-shot weapon may do significantly less than twice the damage of a shot from a non-legendary version of the weapon modded in the same fashion. It does, however, help punching through the target's armor, delivering more of the applied mods' damage.
** Two shot has an ability to provide a slight damage up when applying weapon mods which reduce damage. As it uses the base damage for the second projectile's damage, a mod which lowers damage (such as an automatic receiver) will be averaged with a higher damage rating, giving both bullets slightly higher damage than the weapon would have without Two shot.
** Upgrading a Two Shot Fat Man like Big Boy with the MIRV modification will result in the weapon carpet-bombing a huge area with twelve mini nukes instead of six while simultaneously and massively reducing its range, potentially catching the player in its own fire.
** When applied to an unmodified double-barrel shotgun, it will double its base damage, but cause it to have zero accuracy, meaning it will only be effective at point blank range.
** A Two Shot railway rifle will shoot two railway spikes, and because of this, enemies killed with such a weapon have a chance to drop two railway spikes instead of just one.
** All Two Shot weapons can deliver up to double the damage of their base, unmodified variant. This means that a Two Shot weapon can easily do more damage than an identical weapon with one of the race-specific damage prefixes (Assassin's, Exterminator's, Ghoul slayer's, Hunter's, Mutant slayer's, Troubleshooter's). For example, given two fully identically modified .50 sniper rifles, one a Ghoul Slayer's and one a Two Shot, the former will do 64 base damage to any enemy and (64 * 1.5) = 96 to ghouls; while the latter will do a consistent (as demonstrated above) 101 damage to any and all enemies, ghouls or not. This means that any Two Shot weapon effectively makes all race-specific variants of most weapons obsolete. This can exclude some rapid fire weapons however, as the extra recoil may make them difficult to use. 
** Two Shot fully stacks with the laser musket "cranking" mechanic and doubles or almost triples its output. As a four-crank capacitor and long barrels are available with Science! 1, a legendary drop with 248 damage per shot is potentially available very early.
** While rare, a Two Shot weapon can miss on a critical hit.
===VATS Enhanced===
* Ranged weapons will use 25% less AP and gain 33% increased hit chance; on melee weapons will have their AP cost by reduced by 40%. 
* Low AP-cost weapons such as the Deliverer can easily queue 16 attacks, the maximum amount per use of V.A.T.S.
===Junkie's===
* Works on missile launcher.
* Dark Craving does not count as an addiction for this effect.
==Console commands==
Legendary effects can be added to items through the console by following the next steps:
# Drop the item on the ground.
# Pick up the item in the air by holding E (how one would normally drag ragdoll and other objects around).
# Open console and enter "GetPlayerGrabbedRef." This returns the RefID of the item the player is holding in the air.
# Take note of the returned RefID.
# Look up the ModID below for the desired legendary weapon effect, note it as well.
# Enter the following in the console (substitute the appropriate RefID and ModID): 
# For example, the player would enter in something like this: .
# The item will drop to the ground, and when the player goes to pick it up, they will get an overview similar to the one the player gets when they pick up any given legendary item for the first time.
As a simpler alternative to points 2 - 4, the player can simply left-click on the item when it is lying on the floor. The RefID will then be displayed on-screen just as if one used the mentioned console command. Certain weapons can be challenging to left-click when dropped, so if this is unsuccessful, use instead.
The player cannot stack several mods on a single item, but they can replace a mod with another one via the console.
If one is experiencing difficulty selecting the item, try dropping it in a settlement, then placing it using the build tool.
==Bugs==
* Enemies that die while frozen respawn in a broken state, laying on the ground immobile and unable to fire.
* Using V.A.T.S. with a Deadeye weapon can cause the game to move at normal speed in VATS, making enemies somewhat harder to target.
 
ru:Легендарные свойства оружия