The size 36 mm main tube is the second widest main tube diameter in use on modern rifle scopes. It is only used by Zeiss and Hensold for their massive, lowlight hunting rifle scopes and the last generation of Hensoldt tactical scopes. The rifle scope is mounted to the rifle with the help of two 36 mm mounting rings. When fastening the screws one must take absolute caution not to over tighten the screw. Doing so can result in marks and scratches on the rifle scope exterior or even worse in malfunctioned rifle scope due to structural compromises. The most force to be used when tightening the screw should not exceed 2.2 Nm. The manufacturers who provide 36 mm mount rings are: INNOmount, EAW, MAK, Recknagel, Rusan, Dentler, Henneberger, Contessa, Blaser, Sauer and Spuhr.
Even though it was an very unusual step for Zeiss to introduce scopes with tube diameter which no one else ever produced, producers of munts followed incredibly fast. 3 years after introduction of Zeiss Victory V8 scopes, there is more than 10 manufacturers of mounts that produce anything from mono-block mounts, individual rings, pivot mounts, custom mounting solutions.
36mm ring mounts have all possible forms, from very elegant hunting mounts with 15mm wide rings to tactical mono-block mounts with 30mm and more wide rings.
Lapping is a process that is essentially lining two mounting rings perfectly to one-a-another. It is done with special cylinders that grind off the excess metal.
In the worst case scenario the axis that runs through the center of the rear ring does not completely match the axis that runs through the center of the front ring. For this reason the scope, if mounted into such rings is under unwanted structural stress. The most obvious problems that occurs due to this reason is less than perfect optical performance, tracking problems, the side focus mechanism can stop working and the point of impact groups can be dispersed.
If the ring is designed in the fashion of 1/3 base of the ring and 2/3 the top of the ring than lapping is not required as the design is plastic enough to bend slightly and adjust its shape to the scope tube. The same applies for ½-1/2 rings mounted on single piece
It may be a good idea to take in consideration to choose the 1/3 : 2/3 rings as they do not require additional lapping to be fitted properly. Or use a single piece mounting base.
Since 36mm mounts are mainly produced by premium mounts producers and are usually expensive, lapping is almost never needed. Due to this reason there is also almost no lapping tools available on the market for 36mm mounts. It is however a good idea to use a ribbon cut from latex/rubber gloves on the lower contact surface in the rings, when mounting 36mm scopes.