I claim the ornamental design for a paintball gun bolt, as shown and described.
FIG. 1 is a perspective view of a paintball gun bolt, showing my new design;
FIG. 2 is a front elevational view of FIG. 1, the rear elevational view, left-side elevational view, and right-side elevational view all being mirror images thereof;
FIG. 3 is a top plan view of FIG. 1; and,
FIG. 4 is a bottom plan view of FIG. 1.
The broken lines in FIG. 3 represent portions of the article that form no part of the claim.