Re: Nikon 3-9x40 ProStaff BDC
We've had Nikon replace both of the 3-9x40 Primos BDC scopes from our 7mm Wby rifles. One was the victim of a fall, and the other lost zero twice (!). Nikon "fixed" the second one after it lost zero the first time and sent it back to us. After some effort sighting it in, it then was 2+ feet high when we arrived at our hunt. That one was sent back recently and replaced with a new one.
Having said that, the BDC feature works exceptionally well, and the second rifle took antelope at 500+ and 800+ yards before the scope took a dump. I would not, however, use them on a rifle with a magnum cartridge. I'm convinced that the 7mm Wby recoil scrambled the insides on that scope, so that new replacement is going to go on a different rifle.