The Minotaur Tactical Shotgun Rails are made with high quality anodized aluminum for sturdy light weight Optic and Laser sight mounting system. Our rails are designed so the same rail will fit either a Mossberg 500/590 or a newer Remington 870. The rail will fit other 18" or longer barreled shotguns if the end user is willing to have their shotgun's receiver drilled and tapped by a local gunsmith. You will noticed our rail stops about an 1" short of the end of the 18" barrel shotgun. This is an intentional design characteristic of our Full Length Picatinny Shotgun Rail This will provide room for the Minotaur Tactical Muzzle Break/ Door Breach/ DNA Collector for Remington 870 and Mossberg Home Defense Shotguns. Installation is simple and requires no gunsmithing skills beyond handling a simple screw driver and Allen wrench.