GEN 1, GEN 2 or GEN 3 UBS-12 UNITS ALL INSTALL THE SAME WAY
NOTE: A proper installation is not finished until the three top screws and the one large REAR screw is installed. If you plan to keep your UBS-12 mounted for a long time, consider adding blue LOCTITE on all screws during installation for maximum secureness.
The "rear screw" connects where the buttstock connected into your shotgun. The UBS-12 works with any remington 870 or clone. Due to the fact that there are hundreds of different manufactures making clones, with a range of different thread sizes and pitches, the UBS-12 is shipped without a rear screw.
Included with your UBS-12 mount is an installation kit of 3x NORD-LOCK X series washers and 3x #6-48 screws. These screws and intergrated screw pattern will provide a direct bolt on option to some models of 870 or clones.
When doing a fresh UBS-12 install on a shotgun without prethreaded holes, we recommend using a larger screw such as a #8.
Some 870 style shotguns have aluminum receivers while some are steel. A #8-32 UNC (Coarse Thread Pitch) would be best suited for aluminum receivers while a #8-36 UNF (Fine Thread Pitch) would be best suited for steel receivers. IF YOU ARE DOING THE INSTALLATION YOURSELF AND HAVE ANY QUESTIONS, PLEASE CONSULT A CERTIFIED GUN SMITH OR LOCKHART TACTICAL!
After your shotgun is fully connected to the UBS-12 mount and all (4) screws are installed you are ready to mount your under barrel shotgun to your host firearm. We recommend checking the tighteness of all (4) screws after your first 25 rounds of firing.
