20 Gauge Round

 is a type of ammunition in Fallout: New Vegas.

Characteristics
20-gauge shotgun shells are very similar to their better known cousin, the 12 gauge shotgun shells. 20-gauge shells are a plastic tube with a brass base. The primer, gun powder, and wadding are compressed into the bottom of the casing and the projectiles are place on top, held by the plastic tubing. Most common projectiles are small lead or steel balls called shot. In a slug version of a shotgun shell a single large sabot is used in place of the shot. A magnum shell would include more grains of gun powder, thus increasing the velocity the the projectiles when fired. Being smaller than 12-gauge shells (smaller numbers mean bigger in "gauge" speak) 20-gauge shells include less powder and less shot. The benefit the the smaller shell size is less "kick" when fired.

Variants
20-Gauge Slug -- Fires a solid metal projectile to ensure maximum damage at greater distances. The in-game shell description notes the reduced spread, but fails to mention that it reduces the number of projectiles fired; this can make the value of slug shells less readily-apparent. The damage of slug shell is equal to the total projectile damage of one standard shotgun shell.
 * Value - 2
 * Gun Spread - x0.35
 * Projectiles - 1

20-Gauge Magnum -- Magnum caliber shells hold more powder, resulting in higher muzzle velocity, which inflicts more harm on your victims. Unfortunately, the extra blasting power also deteriorates your shotguns that much faster.
 * Value - 3
 * Gun CND - x1.15
 * Damage - x1.15

Used in

 * Sturdy caravan shotgun
 * Caravan shotgun
 * Lever-action shotgun
 * Single shotgun

Appearances
only appears in Fallout: New Vegas.