In Mortal Kombat 3, Stryker uses a Hand Gun as his long range projectile move (along with his grenades). He can only do this as a special move and in Mortal Kombat: Armageddon, it is replaced in the favor of a machine gun.
The pistol returns in Mortal Kombat (2011). It is used by police officers, Stryker and Kabal are the only known. Stryker could use his pistol again with his special move Pistol Shot. In Story Mode, his partner Kabal uses his gun in cutscenes only but cannot use it during gameplay because it was removed by Kano after abducting him for operation.
In Mortal Kombat X, the character Cassie Cage can be seen using dual pistols with moves like Single Shot.