What is the best laser? Well, usually putting a laser pointer on a rifle is a bit unnecessary. However, if you really want one, I suggest you use PEQ. These are a little heavier than a single laser, but it is one piece. It is a flashlight, a red laser, and most importantly an infrared laser. There are several of them on my rifle. I almost never use laser or flashlight functions. I almost always use infrared lasers for night vision.
Basically only people can see the laser, it is very useful when something is moldy at night. As they say, it is better to always prevail. Do you see those lasers? Those are visible to the naked eye. Only when NVG is on. It means that the darkness is your best friend. Assuming there is a laser gun, will the beam travel slowly or fast, and will the distance affect it? The laser gun does exist as an experimental weapon.
For example, the airborne laser is one of the most ambitious: a beam of light shoots out at the speed of light. It is still affected by distance, and the intensity decreases in inverse proportion to the square of the distance in a vacuum. In the atmosphere, it drops faster due to the scattering of air turbulence. This is why it is installed on the aircraft. The idea is to launch ballistic missiles in the upper atmosphere, where turbulence and weather factors are much smaller.
The project has been abandoned. The main difficulty is that, unlike anti-missile missiles, the laser pointer must remain pointed at the same point on the target for at least many milliseconds. This can be extended by countermeasures such as rotating the target or providing it with ablative coatings. This, combined with the difficulty of defending the ABL aircraft itself, makes it an impractical weapon.
As for what optics to choose, the same is true for the original point. I prefer green laser pointer to smaller ones because they come out of the holster faster and only use power optics, which can be scary. I also prefer the slider for specific optics or milling, the unified tactical atomic installation is very good. The dovetail shape of the mount allows the optical element to maintain its zero position well, which is a concern for other adaptive platforms.