The ornamental design for a crossbowstock, as shown and described.
FIG. 1 is a top perspective view of our crossbow stock design with the stirrup portion shown in broken lines for purposes of illustration only and forming no part of the claimed design;
FIG. 2 is a bottom perspective view of the crossbow stock of FIG. 1;
FIG. 3 is a side elevation view of the crossbow stock of FIG. 1;
FIG. 4 is another side elevation view of the crossbow stock of FIG. 1, which is the opposite side view of that in FIG. 3;
FIG. 5 is a top plan view of the crossbow stock of FIG. 1;
FIG. 6 is a bottom plan view of the crossbow stock of FIG. 1;
FIG. 7 is a rear elevation view of the crossbow stock of FIG. 1; and,
FIG. 8 is a front elevation view of the crossbow stock of FIG. 1.