12 Gauge Round

The 12 gauge shotgun shell is a type of ammunition in Fallout: New Vegas.

Characteristics
The 12 gauge shell reappears in Fallout: New Vegas, with the usual buckshot load as well as slugs. A specialized beanbag shell also exists, for pacifist players, as well as magnum and coin shot shells. A cheap and well loaded source of gun powder for hand loading, due to the 12 gauge shell being bigger that the 20 gauge shotgun shell.

(The "gauge" measurement originates from muzzleloader guns: a ball of lead fitting into a "n-gauge" barrel would weigh 1/n pounds. Thus a 12-gauge gun is caliber .73, a 20-gauge gun is caliber .62)

12 gauge, bean bag
Bean bag rounds are less-lethal shotgun ammunition commonly used by Law Enforcement to quell riot situations. Bean bags inflict Fatigue Damage and stun a target momentarily. While they are regarded as the weakest form of shotgun shell, they can be very useful should the player encounter powerful opponents, such as deathclaws, by utilizing the bean bag rounds to first stun them and then switch to another type of ammunition or weapon to finish them off while they lie helplessly on the ground. For soft targets, bean bag round still can drain their health and kill them(multiple shots will be required).

12 gauge, coin shot
Coin shot is an improvised buckshot round using Legion Denarii as the projectile. The end result is an ammunition identical in damage to a magnum buckshot round, but one which has a chance of leaving coins in targets it damages, as well as an extra "pellet" as shown by the damage indicator when using this type of ammunition. In V.A.T.S. Denarii can be seen leaving the barrel of the weapon in certain shots. Coin shot is regarded as a better ammunition for trading, due to its dramatically increased value.

12 gauge, magnum
Magnum shells are standard buckshot shells fitted with a higher internal powder load, increasing velocity and stopping power. The downside is more damage done to a firearm due to the higher overall pressure, resulting in more regular maintenance.

12 gauge, slug
Slugs are solid metal cylinders with a rounded nose and rear cavity (this sets up an equilibrium between the aerodynamic forces and the center of gravity to make the slug fly relatively straight; it is somewhat like a shuttlecock) used to replace shot (pellets). Slugs are often rifled, which imparts little or no spin to the projectile. Instead, the actual purpose of the rifling is to decrease the bearing surface of the slug to the barrel, This reduces friction and increases velocity, and allows the slug to safely be swaged down when fired through a choke.

12 gauge, dragon's breath
A sub-type added with the new add-on Gun Runners' Arsenal, these zirconium-based pyrotechnic shells function as a short-ranged flamethrower, having an incendiary effect on targets for 5 seconds. Though not typically used as a weapon, this type of shotgun cartridge is commonly used on army air bases to scare away flocks of birds before takeoff.

12 gauge, 4/0 Buck
A sub-type added with the new add-on Gun Runners' Arsenal, this shot sacrifices quantity for quality, in other words there are fewer projectiles overall but they're larger and pack a bigger punch.

12 gauge, pulse slug
A sub-type added with the new add-on Gun Runners' Arsenal, these slugs punch through armor more effectively, and the target gets an extra kick from an Electromagnetic Pulse triggered by the impact. This also means they are very good against robots and anyone wearing power armour.

12 gauge, flechette
A sub-type added with the new add-on Gun Runners' Arsenal, these shells have had their traditional shot replaced with tiny metal darts that are great for armor penetration, but are not quite as damaging.

Variants
* See bugs.

Weapons using this ammunition

 * Hunting shotgun
 * Dinner Bell
 * Sawed-off shotgun
 * Riot shotgun
 * Big Boomer

Bugs

 * Although 12 gauge bean bag ammunition specifies that it causes 250 points of fatigue damage, in practice each shot will only induce 50 points of fatigue. Furthermore, all shotguns inflict a minimum of 12.25 points of damage, regardless of damage penalties or effects of Damage Threshold or Damage resistance. These two issues mean that attacking a target with bean bag shells will most likely result in the target's death before it is ever knocked out due to Fatigue.
 * Additionally, bean bag shells can inflict fatigue damage on robots, something which all other sources of fatigue damage specifically avoid. This makes it possible to "knock out" robots, most of which can endure no more than 100 points of fatigue before being rendered unconscious.
 * PC users can fix the above bugs with this user-created fix.
 * 12 gauge slug shells have a listed 30% chance of dropping an empty hull, but they do not actually reference the 12 gauge hull item, so they don't actually provide 12 gauge hulls.