I've got one from SiteLite that is great! It's not cheap (~$100), but it comes with an access code for their free ballistic software. I've used it on all my rifles, and it's gotten me on paper out to 100 yards. Saves so much time and ammo, not having to start at 25, move to 50, then finally out to 100.
You input your bullet specs, height above bore, zero range, and distance from the target (e.g., if you only have a 25-yard shooting range, you can still boresight for 100 yards), and it will let you print a target showing where to put the laser and where to move your crosshairs or sight to.
It's much more difficult to explain than it is to do... :lol:
Bore sights are good for getting a rough zero, but when I check zero I do it at 25 yards using the "200 yard battle zero" method. I know the price of ammo is painful but getting a solid zero is bullets well spend IMO.