Paul...I have a Laserlyte boresighter that has done dozens of rifles for myself and friends. It does the job well, just like the Bushnell will I am sure. Think I bought it from Midway USA. I also have two small levels to level and plumb the cross hairs. I learned a fine tuning trick from a gunsmith named AJ on the Realtree forums. Have/get ring alignment tools. See pic below.
If your rings are not lined up, neither will your scope be. I spun these up on my friends lathe a while ago. They are 1" aluminum round stock with a 45* point. You can see what they do. If the rings need shimming under the bases...this is the time to do it. You can also get 30mm round stock to do larger rings.