The ornamental design for a railstopattachment, as shown and described.
FIG. 1 is a left, rear, bottom perspective view of a rail stop attachment attached to a firearm showing our new design;
FIG. 2 is a left, rear, bottom perspective view of the rail stop attachment of FIG. 1 with the firearm omitted;
FIG. 3 is a right, front, top perspective view of the rail stop attachment of FIG. 1 with the firearm omitted;
FIG. 4 is a front elevation view of the rail stop attachment of FIG. 1;
FIG. 5 is a rear elevation view of the rail stop attachment of FIG. 1;
FIG. 6 is a bottom plan view of the rail stop attachment of FIG. 1;
FIG. 7 is a top plan view of the rail stop attachment of FIG. 1;
FIG. 8 is a right side elevation view of the rail stop attachment of FIG. 1; and,
FIG. 9 is a left side elevation view of the rail stop attachment of FIG. 1.
The broken lines showing portions of the design in all figures is included for the purpose of illustrating environment and unclaimed features and forms not part of the claimed design.