The ornamental design for a riflescope mounting ring part with movable accessory rail, as shown and described.
FIG. 1 is an isometric view of the rifle scope mounting ring part with movable accessory rail;
FIG. 2 is a front plan view thereof;
FIG. 3 is a rear plan view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right side plan view thereof,
FIG. 7 is a left side plan view thereof;
FIG. 8 is an isometric view with the movable accessory rail shown in an alternate position;
FIG. 9 is a front plan view with the movable accessory rail shown in the alternate position; and,
FIG. 10 is a top plan view with the movable accessory rail shown in the alternate position.
The broken line showing of shown in FIGS. 1 through 10 is included for the purpose of illustrating portions of the rifle scope mounting ring part with movable accessory rail and forms no part of the claimed design.