To me the mechanical zero on an elevation drum is important, you know that point at which the drum bottoms out. Now if you can set your actual zero to match the physical zero then you no longer have any worries about loosing how many turns off the zero you are, this is particularly confusing when your physical stop is a turn and a bit below your zero.
Confused? I used to be when I first started using a Nightforce having spent many years with single turn S&B drums so I machined a spacer to fit under the drum to act as a physical stop so that when I would the drum down and met resistance I knew I was at my zero, or more accurately 2 clicks/1/4MOA below.
Now I am building these stops for other NF users. Simply set and confirm your rifle at your chosen zero, then measure the distance from the bottom of the drum to the scope body, I use a vernier calliper and take the measurement a couple of times to be absolutely sure it is correct. Now email me you measurement and I will machine a polished aluminium stop ring from 6082 T6 Aluminium. I prefer to supply the ring a couple of thou over stop size to allow fine tuning.
To fit set your scope to zero+2MOA and remove the elevation drum via the hex key on the top, slip the ring over the drum inner, replace the drum and tighten and finally wind down to zero, it will be within a couple of clicks now and all you need to do is gently rub one side of the stop ring with some fine wet and dry and test again. I can usually get everything correct and fitted in under 5 minutes.
If you would like a stop making for a scope other than the Nightforce BR send me the ID and OD of the ring and height and I will machine to suit.