Fixed gun

The fixed gun is a world object in the Fallout:New Vegas add-on Old World Blues.

Characteristics
The fixed gun is a pre-War fixed artillery weapon that was used by the Big MT research facility for various tests over the years. Such artillery pieces have far greater range than their mobile counterparts at the expense of being stationary.

Old World Blues

 * Two exist at the X-7a "Left Field" artillery launch, one of which can be used to open a crater in the X-7b "Boom Town" target zone, revealing a hidden cache.

Variants

 * Howitzer, a mobile gunpowder artillery piece in use all over the wasteland.
 * Anti-aircraft gun, a stationary anti-aircraft cannon using many of the same principles as gunpowder artillery.

Behind the scenes

 * The use of the gun in order to open access to a secret cache is similar to the use of a howitzer during the Fallout 2 quest, Find a way into the Sierra Army Base and the use of the Bradley-Hercules against the Citadel in Fallout 3.