I have a mark 2 on my 300wsm. Called leupold, gave them my data and $60. Two weeks later I received my elevation turrent. I have since tested it at most all ranges between 300 and 1000yds. It was dead nuts on the money at all ranges I shot. It is very liberating. For several years I have been using ballistic plexes of some sort or another and burned up a lot of ammo finding the best compromise setting. The precison of a lazer engraved elevation turrent is the way to go hands down. My buddy did the same on his 300 ultra mag about a year and a half ago. Last November I watched him drop his bull elk at 642 yds. X-ringed him. If you don't have target turrents on your scope you have to send it in to have them installed. It ups the cost to about $130. I received excellent service and advice as usual with leupold.