The ornamental disign for a pistolbarrel, as shown and described.
FIG. 1 is a left side elevational view of a pistol barrel, the showing of a
pistol base is for illustrative purposes only and forms no part of the
claimed design;
FIG. 2 is a plan view of the pistol barrel;
FIG. 3 is a bottom view thereof;
FIG. 4 is a front view thereof; and,
FIG. 5 is a right side elevational view thereof with the right elevational
side view being a mirror image.