Army Pistol

The Army Pistol was a weapon in V2 of the Facility, before being scrapped due to V2 not being released. However, it is still in the border game with multiple different variants.

In-game
When looking at it up close or in first person, the pistol resembles a FN Five-seveN pistol chamber for the cartridge it was chambered for, FN 5.7x28mm. Based on the border game, it may have done the same damage both there and in the border (32 HP), so as a result, it was made to have a 8-round capacity (possibly due to the fact that if it had a 20-round magazine, which the real Five-seveN uses as its standard magazine, it would have been extremely overpowered). Also, if clicking fast enough, it essentially became a discount version of an automatic gun in-game.

Interestingly enough, it did more damage than the MPX, though this could've been due to cartridge differences (9x19mm for the MPX vs 5.7x28mm for the Army Pistol)

One Army Pistol
The One Army Pistol is a variant of the Pistol in the Check It Border given to Border Directors. Other than the different name and presumably faster fire rate, there is no significant difference between it and the regular Army Pistol.

Golden Army Pistol
The Golden Army Pistol is an admin weapon in the Check It Border. It can be seen here, in BloxyColaThief's inventory, albeit unused.