Plasma gun (Fallout 4)

The plasma gun is a weapon in Fallout 4. Variants include the plasma pistol, plasma rifle, plasma scattergun and plasma thrower.

Characteristics
Plasma guns are a versatile urban warfare weapon that can be used as a pistol, sniper rifle, semi-auto rifle, assault rifle, shotgun or even a 'plasma flamethrower.' It is usually encountered later in the game and found on technologically advanced opponents, although at even higher levels it can be found on raiders and legendary enemies.

Compared to the previous iterations, Fallout 4's plasma projectiles travel much faster and cause both ballistic damage and energy damage as opposed to only energy damage. It is a good weapon for facing high tier enemies, with its best burst damage output coming from a fully upgraded plasma rifle in a non-automatic format and proper investment in the Rifleman perk can feature monstrously high damage outputs (inflicting more than 100 damage in both ballistic and energy damage) with the only non-explosive weaponry capable of reliably exceeding it in damage output being the Gauss rifle. Unfortunately, the plasma bolts (despite being faster than in previous renditions) still have a noticeable lag time, potentially limiting the utility of plasma sniper rifles at distant moving targets unless V.A.T.S. is used.

The best DPS, gun-disarming and limb-crippling capability come from a player character using a fully upgraded plasma flamer pistol with a maxed out Gunslinger perk, as the perk will increase the range of the flame as well as retain its fully automatic firing mode. With legendary mods such as bleeding or two-shot, it's capable of knocking super mutant behemoths down before they can get within significant range, or staggering multiple close-range assailants to the ground before they can return fire. It basically serves as the ultimate flamethrower-based weapon in-game due to its range, fire-rate with flamer barrel attachment, and the significant disarming effects of the Gunslinger perk.

Not only is the weapon itself much rarer than other energy weapons, but the plasma cartridge ammo is also much more valuable. This reduces the viability of this weapon as an all-around firearm.

Due to the downsides of energy weapons like this, such as the laser gun and Gatling laser, all lacking the ability to add a suppressor, this weapon will continue to attract more attention to the player character, even in its best form.

Plasma guns are the lightest ranged weapon class in the game, closely followed by laser weaponry. A fully upgraded plasma gun in a rifle type variation weighs just over 8 pounds while a top tier laser gun in a rifle configuration weighs around 9 pounds, making both weapons even more useful as a powerful backup weapon that can be carried around at all times without weighing its owner down too much.

Variants

 * Experiment 18-A - a unique plasma rifle with Rapid Legendary effect. It is sold by the Synth requisition officer in The Institute.
 * Sentinel's Plasmacaster, a unique plasma pistol with the Instigating Legendary effect.I is sold by Proctor Teagan onboard the the Prydwen after Completing A New Dawn.

Locations

 * Vendors start selling plasma guns starting at level 16.
 * If the Sole Survivor enters Nuka-World and is below level 16, Aaron Corbett can sell this weapon.
 * Arturo Rodriguez sells at least two at higher levels.
 * Legendary plasma guns start dropping at level 24.
 * Level 3 weapon shops in settlements always have three for sale.
 * Higher level Gunners are sometimes equipped with plasma guns.

Bugs

 * The plasma thrower is bugged and has a high (though not 100%) chance of dealing no damage each time the trigger is pulled. This occurs while using V.A.T.S. or immediately after using V.A.T.S.
 * This bug only seems to happen in V.A.T.S. or immediately after exiting V.A.T.S., however if one isn't close enough to one's target it will not deal damage, being much like a flamethrower.
 * The plasma thrower is completely bugged in V.A.T.S. The weapon is shown to attack in short flame bursts, however, only the first puff of plasma in V.A.T.S. will deal damage, one shot will be used regardless of how many attacks are queued up, and every attack queued after the first will supercharge the critical meter.
 * With the rifle variants, firing and then swimming will cause the weapon to be held like a bat and prevent firing the weapon. To fix it, just unequip and re-equip the rifle.
 * Depending on which variant (Rifle or Pistol) you acquire before turning the weapon into a Plasma Thrower, it will only get damage buffs from (Gunslinger or Rifleman) and will not get buffs from Commando.