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Should I lap a one piece mount?


Full Member
Jun 27, 2012
phoenix az
bought another rifle ruger rpr orderd the nxs scope and an Adm one piece mount. My question is should I lap the mount before installing the new scope or just drop it in and go. My custom rifle has nightforce rings I didn't lap those and it's a tack driver thanks for any input.
Being a vertically split design, you might be fine or you might not. Normally a 1 piece system removes the need of lapping.
You may want to rethink your choice of mount. See Frank's thread about the problems with vertically split rings...
With my experience, which is likely less than a lot of guys on here. BUT, if you buy a set of quality rings, whether 1pc, or 2pc; the machining tolerances now days are generally so precise, that lapping is no longer necessary, as it may have been in the 'olden days' where machining was not as precise. I have seen high quality rings become worthless, because lapping (can) remove too much material, which causes the I.D. of the rings to increase, resulting in the scope sliding under recoil. Just my input, for what it's worth.
Thanks everyone.I did read Franks post and sold the mount without even mounting it. I ordered Seekins precision rings which I use on my other rifle and like
I've used ADM mounts and Warne Tactical rings (also vertically split, got them with a used scope I bought) and it is possible to install them in such a way that zero shift is pretty unlikely.

The thing you have to realize is the relatively low torque values you are told to use is to prevent crushing the scope main tube.
The screws that attach the rings to the mount (in the ADM) and to the rail (Warne) can be torqued to 50 or 60 in/lbs as long as the screws on the top of the rings are not overly tight, but it's about the order in which they're tightened, and care must be taken to ensure the rings are aligned with the scope tube, too.
In other words, with the top screws loose, snug the bottom screws then back off as little as possible, maybe a degree of rotation. The rings should be able to shift fore and aft ever so slightly but not side to side.
Snug the top screws, no more than 5 in/lbs.
Snug the bottom screws to 10 in/lbs, at this point the ADM rings are actually metal to metal with the mount, and the Warne rings are metal to metal with the base.
Loosen and finger tighten again the top screws to ensure that the geomtery of the rings are aligned with the scope tube, but when you tighten the crap out of the bottoms screws in the next step you are not crushing the scope tube.
Torque the bottom screws to 50 in/lbs
Torque the top screws to 20 in/lbs
This can hold you over long enough until you scrape together the coin to buy Seekins rings (my go-to but of course ARC M10, etc are also great) or a Spuhr or Aadland (or similar built like a brick shithouse to extremely tight tolerances) one piece.