well the "up and down" adjustement (the top dial) on there should be calibrated for either imperial minute of angle, metric minute of angle or millradian. imperial moa = 1 inch at 100 yards, metric is 1 cm at 100 meters and if my memory serves me right 1 millrad is 3.49 inches at 100 yards. if you can get yourself a good chrony you can find the b.c. of your bullet and your muzzle velocity which you then plug into a ballistic calculator which would give you your moa/millrad drop. for example my deer rifle has a muzzle velocity of 3235 and a b.c. of .621 so at 500 yards i have about 7 moa of drop. on your scope that should mean i would dial the turret up 28 clicks if each click equals 1/4 imperial moa. its simple to some, hard to others and a overall pain in the arse.

that other dial on the side is used mostly by airgunners to find range. basicaly theres something called field target shooting where in most cases you need to hit a target 1/2 inch or smaller with no range finders so guys buy big scopes like those. you just zoom in, use that big side dial to focus and read the range on the side.

just my opinion that scope has no place on a muzzleloader. BSA is a airgun company and that is meant to be a feild target airgun scope. that scope is overkill, and coming from me the guy who over kills everything, thats a big statement