I have an old Leupold Vari XIII. 3-10x 50mm scope in near new condition. However, I have no specification data on it., only the instruction manual. Is any one familiar with it? The instruction says that it has click markings at 1/4 minute with 15 minute dial. It doesn't say the range of adjustment. I will be very grateful for kind information about the range of adjustment on this scope. Is it still serviceable for long range use < 750 yards, using the click dialing for compensation? If so, I will invest in 20 moa base and search for turret adapter for dialing ease. Thanks.