NC Shotgun Tube Clamp connects the magazine tube and barrel. Fits most shotguns when used with a Nordic Components Extension. Includes a tactical mini-rail. This is made to fit shotguns using a Nordic Components magazine tube extension. Our tube has an OD of 1.06″. NOT FOR USE ON BROWNING AUTO-5 or any Recoil operated shotgun where the barrel moves to eject and load the shells! NOT FOR USE WITH THE REMINGTON M887 or MOSSBERG 590, 835, 935 and 930 SPX Models, or any Mossberg shotgun with a heavy walled barrel.