The biggie with any collimator is to check its alignment, by putting it on several rifles that are already sighted-in. You'll discover that bore-scope alignment will vary somewhat, but will be in the same general area. The Bushnell, like some other more sophisticated collimators, has a grid reticle that can be adjusted to line up with the bore on sighted-in rifles. I did that years ago, and it works well, but as noted not for all barrels. Probably the most versatile in my collection is the Wheeler Engineering laser model. I've even used it on 12-gauge slugs guns.
Thanks for this!
An order for a Wheeler Engineering laser bore sighter was entered yesterday. (After all these years without.) Lever action, pump action and now an in-line muzzle loader besides upgrading scopes pushed me over the edge.
