Laser Sight Collimation: Pistol
If you think about it, there's only two ways to collimate a laser designator...
1) Sweet Spot: The laser is set to converge with the bullet at a distance predetermined by the shooter--the sweet spot. The laserís point of aim (POA) will be offset more or less, inside or outside the selected sweet spotís point of impact (POI). This is the only way to set up the laser/light combos, where the laser emitter is far from the gunís bore axis.
2) Offset: If the laser emitter sits close to the gunís bore axis, it can be set up to run parallel to the bullet's path, out to practical shooting ranges. The offset--say it's a half inch--is a known value, and is ignored or compensated for by the shooter. This is how the LaserMax guide rod lasers are set up, since the laser emitter sits so close to the bore axis.
Both approaches work, and are plenty accurate for self-defense. Neither is intended for precision sniping.