Or else I borrow my buddy's collimator. I've used the Leupold a few times to check zero on a gun but the zero on the gun was OK anyway. Never did figure out how to trust it when mounting a scope. Recently mounted a scope and bore sighted it till I was happy. Put the Leupold boresighter on it and it looked like it should be pretty good.

I just bought the Leupold zero point boresighter and it is rather difficult to understand the directions. I understand how to measure the elevation from the center of the barrel to the center of the objective axis.