Re: military calibrated turrets/ss 20x42
Like any ballistic calibrated turret knob, they'll be dead on some of the time, close most of the time, and serve a good purpose for when you need a quick reference for yardage changes. At least that version doesn't remove the moa markings and are only supplemental indicators.
Changes in density altitude will always cause your impacts to shift. If you need the speed and want to spend the money, then go for it. If you are just looking for a cheat reference, you're better off making your own drop cards for different conditions or getting a cheap ballistic smart phone app that will actually be accurate.