Yes there is a caliber guide. By which caliber you have determines if you use the large or small triangle on your scope and if you zero 2 or 3 hundred yds. The leupold web site I think has this information under b&c reticle. I don't think its accurate enough that if you zero at 200 your going to drill the bullseye at 450 but it should get you to within an inch or to. Which is fine for me on a elk sized creature. Heck my trigger squeeze would throw me offmore than that at 500. Like I said I didn' kill one with it yet, But it has to be better than , holding the cross hair level with the top of the horns and pulling the trigger.