With my viper and 20moa base on the 308 I'm turned almost all the way down for the 100 yard zero. It can be hard to say where it will be at first. I set my rifle on the bench in the shop with the bolt out and aim at a orange sticker on the white wall through the bore and move the scope to get on the dot. I'm too cheap to buy a bore sight or laser when I can do that.