The better boresighters are optical. You can get laser boresighters to work but I highly reccomend the interchangable pilot optical boresighters to a LOT better and more precise job. The main thing to remember is that boresighters are designed to get you on paper-NOT sighting in exactly.
They also don't take into account bedding,barrel vibration,or weight of bullet used. Whatever you choose-be sure and follow up to sight it in by shooting it to be exactly where you want it.