The ZFK55 Scope

[Pierre]

First, unless you are very experienced in servicing Swiss Scopes........ do not attempt disassembly.
My visiting Father In Law is extremely experienced. One of the three who developed the world's first Atomic Microscope for Stanford University, R&D Head of Dept. for Jenkyl & Davidson, Head of R&D for Swift Instruments and a few other I don't remember........ he's qualified to do the job. This is what he discovered, and this applies to all zfk55 scopes.

All of them come with windage/elevation ball detents, however few of them can actually be felt when turning the knobs. Reason? Highly likely weak or broken springs under the single ball itself. A hole, the exact size of the ball and the spring is drilled into steel ring container. The spring is dropped in, the ball goes in on top of it and then the edge of the drilled hole is very gently and precisely "peened" with a circular tool of the correct diameter, trapping the ball just above diameter center.

There is, apparently, grease of a synthetic base in that ball detent hole as well as in the outer casing. The age may be the culprit for that spring to have weakened. Without that spring pressure, the ball simply either engages the detents very weakly or not at all. We're field testing on sent to us today. It did have a small screw floating in the windage housing, but that was only the reason for the reticle "jumping". The spring in this particular scope is either broken or extremely weak.

Having reassembled the turret, we found that there is very little resistance in the turret knob. We'll have two options to offer the owner later today. One, disassemble, remove the ball and spring, re-drill that hole 1/1000th larger, use a ball that's 1/1000th larger than the original and actually fabricate the required tool for "peening". Fortunately, my FIL is a machinist and more importantly, a micro-machinist. No ideas as of yet on the cost of doing this initial process, but both turrets would need to be done.

Second option: Add an extremely heavy grease, filling the inside of the turret to stabilize it an prevent the reticle from moving when the rifle is fired. We'll see about that one with field testing, so................

Don't get too bothered about your scope not registering either felt, or actual detent locking. You're all (including me) in the same boat

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.