12.7mm Round

 is a rare type of ammunition manufactured by Hauer Premium in Fallout: New Vegas.

Characteristics
The Hauer Premium Show Stopper 12.7mm civic defense round is a consumer-grade pistol round of identical diameter to the military-grade .50 caliber, but less powerful.

12.7mm Round, Hollow Point
Hollow point bullets mushroom and break up on impact, causing massive trauma on fleshy, unarmored targets. However, this also means they break up when they hit things like armor plate, drastically reducing the weapon's penetrating power.

12.7mm Round (Junk)
The Junk Rounds perk from the Dead Money add-on was at one point intended to create ammunition of a special subtype. Called Junk or JNK, these rounds all provided the same modifiers regardless of caliber: 0.75x to Damage and 1.5x to Gun Condition. The rounds remain present in game code but are not placed in any locations, and if somehow obtained cannot be used in any weapons, even those chambered for the correct caliber.

Curiously, the presence of 12.7mm JNK rounds indicates that the perk was to provide a recipe for crafting 12.7mm rounds, though the final version of the perk does not include one. This may be a bug or oversight, similar to 12.7mm ammunition's initial absence from most merchant inventories and the lack of a crafting recipe for the ammunition.

Weapons using this ammunition

 * 12.7mm pistol
 * 12.7mm submachine gun
 * Survivalist's Rifle

Notable locations

 * Vendortron will sell these at relatively low levels.
 * Knight Torres sells 50-200 rounds at the Hidden Valley bunker.
 * The Arms Merchant at the 188 Trading Post semi-regularly sells 12.7mm ammunition.
 * You can find 10-30 rounds in the Bloodborne Cave. Two twelve round boxes, one by each 12.7mm weapon in the cave.
 * In higher levels, the merchant Daniel Contreras in Camp McCarran sells more than 1000 rounds.
 * In higher levels, the merchant Cliff Briscoe in Novac starts regularly selling 12.7mm ammunition.
 * If you are at higher levels, Great Khans, Legionaries, and Fiends will occasionally carry some rounds.
 * Bardon at Hoover Dam has a couple thousand 12.7mm rounds in stock at any given time.