This pistol has a slightly higher damage compared to the Colt .45 found earlier, and wipes the floor with all of the 9mm handguns. It has a lower ammunition capacity and a lower range than the .45, but most targets won't take more than 6 shots at close range to drop. Eventually, though, you'll want to switch to either a Desert Eagle or a .44 revolver, if only for the adaptability and abundance of .44 ammunition.
Carried by the Beastlord between the deathclaw matriarch's pen and the civilian pens in Mardin.
One can be found in Peoria, inside the locker that also contains an M16A1.