As I noted in a earlier post on this thread, for the best use a collimator should be "sighted-in" by sticking it on the muzzle of several sighted-in rifles, and noting where the center of the reticle ends up on the collimator screen. That point will vary some from rifle to rifle, due to barrel contour, cartridge, etc., but you can generally come up with an average point which will be pretty close for most rifles.
Agreeed.
