The ornamental design for a beltbuckle, as shown and described.
FIG. 1 is a front isometric view of a belt buckle in accordance with the new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right side elevation view thereof;
FIG. 7 is a left side elevation view thereof; and,
FIG. 8 is a front isometric view thereof, shown on a belt strap.
The broken lines shown in FIG. 8 are directed to environment and are for illustrative purposes only; the broken lines form no part of the claimed design.