Love the RB7 rail for the Mossberg 500, but have a Mossberg 500 breacher barrel? This rail is for you! The RB7MB is specifically designed to work with the OEM Mossberg 500 breacher barrel. The specialized clamps are a custom design that lock the the rail in tight.
** If you have a takedown screw instead of a magazine nut, you will need the RB7M rail. If you have a magazine nut, you will need the RB7MB.**