The ornamental design for a rifleholdingtool, as shown in the figures.
FIG. 1 is a perspective view of a rifle holding tool showing my new design;
FIG. 2 is a front plan view thereof;
FIG. 3 is a back plan view thereof;
FIG. 4 is a top view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a left side view thereof; and,
FIG. 7 is a right side view thereof.
The broken line showing of portions of the rifle holding tool is included for the purpose of illustrating environment and forms no part of the claimed design.