I'm certainly not going to take any credit here as it was someone else who tried it-I just tweaked it a bit. As we all know, getting the factory zero stop from Nightforce is a first class pain in the ***-understandably so, as Nightforce is filling .Mil orders that come with the option. Well, I find the value in having a zero stop to be immeasurable. I can't stand counting rotations with the possibility of losing count or forgetting to set the knob back to zero before leaving for the range, only to be frustrated the next time you go to the range and wonder why your zero is off.
It seems that there are 3 options you can use for a DIY zero stop. 1 isn't really DIY and requires permanent modification to your scope and the others aren't overly difficult to do, with 1 being easier than the other. 1 method that I've seen offered required drilling and tapping a hole under your knob. A screw is then inserted and it can be rotated to adjust for the zero stop. The other method is to shim the knob, by either adding them to the exposed circumfrence between the knob and turret housing. I find that to do this right requires tools that I don't need as as lathe and mill would make the work much easier.
The option that I tweaked was to shim under the knob itself. It's fairly easy to do and cost for materials is a grand total of $2.20 if you have the tools on hand.
-4 pack of 1"x13/32"x1/16" flat nylon washers from Lowes, etc.
-Drill with 31/64" drill bit
-Case mouth chamfering tool or Dremel with appropriate style bit
-Allen wrench (for removing knob from scope)
The outside diameter of the washer fits very nicely inside the turret, the inside diameter needs to be opened to fit over raised wall inside under the knob. I used the 31/64" drill bit to open up the inside diameter, which allowed for a really tight press fit.
I used a 1/2" bit but it allowed for too much slop, so I opted for the smaller bit. To make it easier to insert the washer, I used the case mouth chamfering tool on both sides of the washer to make it easier to fit. Use the razor to clean up and burrs.
Insert the washer inside the knob and test the fit.
I got lucky in that 2 washers gave me 1MOA of down below my zero. If I turned harder, I could squeek out another 1/2MOA. You have to test the fit yourself. You might have to take one of the washers to a sanding block to adjust the thickness to get the knob to stop where you want it.
There's 2 things I need to add here-I wouldn't use metal shims to do this as it wouldn't be too difficult to have the knob screw pull through the brass "spud" that actually rotates to make adjustments. With nylon washers or plastic, they should have enough give that the above shouldn't happen.
The second is that this isn't a purpose designed assembly such as the factory not so easy to get option. I could definetely use this during the daytime as I would have a rough idea of when I'm getting to my zero and still see the zero or hash marks at a glance. It works perfectly for that. I wouldn't use it at night as it wouldn't be too dificult to over turn by 1/4MOA or so if you were in a rush.