The ornamental design for a railclamp with accessoryclasp, as shown and described.
FIG. 1 is a front perspective view of a rail clamp with accessory clasp showing our new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken line portions showing gun barrel rails and flashlight accessory in FIG. 1, and bolt, threads and recess in FIGS. 3-7 are shown to illustrate environment only and form no part of the claimed design.