The adjustable firearm trigger mechanism and method of adjustment includes a firing pin block bar, a pivotally trigger shoe, and a link mechanism interconnecting the trigger shoe and the firing pin block bar. The link mechanism includes a sear bar coupled to the trigger shoe for rotation upon pivotal movement of the trigger shoe, and a push rod slidably disposed in one of a plurality of user selectable push rod holes in the trigger housing between a first pivoting end of the sear bar and the firing pin block bar. A trigger pull adjustment assembly is disposed between a second pivoting end of the sear bar and the trigger housing includes a trigger pull adjustment screw mounted in a threaded passage of the trigger housing, and a sear bar return spring abutting the trigger pull adjustment screw and inserted in a portion of the threaded passage of the trigger housing.