Any laser pointer with internal threads on the rear. Both can be screwed onto the end cap of the bullet gun magazine tube. However, if there is no flat milling on the surface of the end caps, they cannot be well supported. Even then, they are not as safe as barrel mounts. You can buy a barrel to replace the Remington 870 end barrel, but only for certain models of shotguns with the same thread. Look for the laser pointer sight model.
A better choice is a simple barrel or tube laser pointer that can be mounted on any single-barrel shotgun. And the price is low. If the length of the lens barrel is too short, they can be installed in front of the lens barrel or on the lens barrel. What type of laser should I use on a bullet gun? This laser is visible at 50 yards with a diameter of 2 yards? That's not how lasers work. Any laser sight in the world can be seen from more than 50 feet away, but if you want to project a 2 foot diameter point on an object 50 feet away, you need a 2 foot diameter laser pointer transmitter.
When the focused laser beam hits the workpiece, the irradiated area rises sharply, melting or evaporating the material. When the laser beam penetrates the workpiece, the cutting process begins. The laser beam travels along the contour as it melts the material. Usually a jet is used to blow the melt away from the cut, leaving a narrow gap between the cut and the platen. This is about the same width as the focused laser beam. Because the brightness of ordinary light sources is not high, the destruction by light energy can only be carried out within a short distance, and the range is very narrow. After the appearance of the laser, the idea of halo weapons can be realized. The laser can be used as a directional weapon, and the powerful directional laser beam can directly cause damage or disability to the target. It is a high-tech, new-concept weapon that uses the huge energy carried by a bright and powerful laser beam to destroy or kill targets such as enemy aircraft, missiles, satellites, and personnel.