At 71 years things they be changing. I have many types but are harder for me to use. What is the easiest best bore site from 22lr to 500 Jeffery. There is less pep in my steps these days. A lot less range time in my future but would maximized my time for sure.

I've tried cartridge lasers and the old bushnell colminator style. I'll stick with the old bushnell type. they even sell a spud for shotguns.

I use a laser boresighter for my 12 ga. and 20ga. shotguns. I shoot skeet, so it is very easy to verify "regulation" with these.
Peter.

At the shop we use the collimator and the muzzle style laser bore sighters. With either style I highly recommend checking calibration with rifles that are sighted in. If they aren't close send back and get another one. The laser style should be centered in the emitter head so that if you insert it in a rifle muzzle and rotate it the laser dot stays in one spot. If it orbits an axis send it back.

We are currently using a WHEELER magnetic bore sighter.

It has a magnet, and attaches to the muzzle, throwing a green laser dot on the target.

I still like the collimator arrangements for setting up scopes as you can get the scope recticule parallel with the bore without fiddling with strings or door frames. I look at lasers as a way of getting the bullet on the paper at 25 yards where you can see where it's going and work from there but I haven't used it yet with these stupid stupid new primer & bullet prices so I may fine tune the process to cut down on the number of shots.

Whatever type you use, just be sure to take it out of the barrel. We've had some rifles come into the shop needing work.