Heavyweight

 is a perk in the Fallout: New Vegas add-on Dead Money.

Effects
The weight of all weapons over 10 pounds is cut in half. This does not affect weapons modded to weigh under 10 pounds. This is very useful for people who like to carry around large and heavy weapons such as the Minigun and the Missile launcher.

Melee:
 * Bumper sword: -6 pounds.
 * Blade of the East: -6 pounds.
 * Chainsaw: -10 pounds.
 * Thermic lance: -10 pounds.
 * Sledgehammer: -6 pounds.
 * Super sledge: -10 pounds.
 * Oh, Baby!: -10 pounds.

Guns:
 * .45 Auto submachine gun : -5.5 pounds.
 * Anti-materiel rifle: -10 pounds.
 * Automatic rifle : -8 pounds.
 * Light machine gun: -7.5 pounds.
 * Minigun: -12.5 pounds.
 * CZ57 Avenger: -9 pounds.
 * K9000 cyberdog gun : -13.5 pounds.
 * FIDO : -13.5 pounds.

Energy Weapons:
 * Euclid's C-Finder: -7.5 pounds.
 * Flamer: -7.5 pounds.
 * Gatling laser: -9 pounds.
 * The Gatling laser is not affected by this perk if you have the Gatling laser carbon fiber frame installed.
 * Heavy incinerator: -7.5 pounds.
 * Incinerator: -6 pounds.
 * Plasma caster: -10 pounds.
 * Recharger rifle: -7.5 pounds.

Explosives:
 * Fat Man: -15 pounds.
 * Grenade machinegun: -7.5 pounds.
 * Mercy: -7.5 pounds.
 * Missile launcher: -10 pounds.
 * Annabelle: -7.5 pounds.
 * Grenade launcher: -6 pounds.

Bugs

 * May reset