Well, it was a unit that used arbors in the shap of the intended chambering that was loaded into the chamber. You had a small target you had to put on the wall 25 feet away. The whole unit was just cumbersome to me. I didnt have very much space to work with (the 25 feet I mean) and trying to line up the laser was a pain.
When I started using the collimator things became just plain easy. Attatch the proper sized spud, slip into bore and look through the scope. BAM, your ready. No 25 feet, no alingning little laser points on a target on the wall 25 feet away, nothing. Just look through the scope and start turning dials. Plus, like I mentioned, you can use multiple ammo types and weight in one rifle/scope combo just by keeping track of grid co-ordinates. This will cut sighting in time down if you decide to change loads to just double checking it is correct rather than a complete re-zero session.
Brian M.