G/K 43 scope rail question

I switched my original ZF4 "dow" scope and repro mount between my G43's and K43. With the K43 ac45, the iron sights and scope reticle are spot on at about 200 yards/meters while the reticle is vertically centered. Same for my d-block duv44. But when I mount the same rig on my "no number"-block duv44, I have to turn the elevation dial to almost 700 meters to have the scope and iron sights line up. The reticle is then in the lower third of the field of view. When I compare aiming though the barrel and through the iron sights, they are both on target. Any explanation?

This is why the Germans numbered the scope mounts to each rifle. While they are all "interchangeable", as you pointed out, they will not all be exactly sighted in to the same POI. The scope allows for such adjustments.


Brian

This is why individual scope mounts were matched to a specific rifle and numbered. There are small variations, however you can re-zero the elevation and windage for a given rifle as excerpted from some old publication I found a while back. Don't expect a scope mount, especially a repro to hold zero from one rifle to another...

"Turret adjustment was simple. Each turret has three locking screws. To zero the rifle, one first removed the screws from one turret, either elevation or windage. A small circular cover is then removed from the turret top, exposing the center adjuster and thereby allowing the shooter to adjust the reticle as needed. The adjuster moves quite smoothly and is easy to align. Once the reticle is in the proper position, the circular plate is placed back in position and the locking screws are reinstalled. Again, this system makes the early No. 32 Mk1 look like a monkey on crack designed its turret. As in the PU, the ZF-4 does not have an optically centered reticle. You can observe it moving downward as you dial in longer ranges."

Hope this helps!

GunKraut said:

I switched my original ZF4 "dow" scope and repro mount between my G43's and K43. With the K43 ac45, the iron sights and scope reticle are spot on at about 200 yards/meters while the reticle is vertically centered. Same for my d-block duv44. But when I mount the same rig on my "no number"-block duv44, I have to turn the elevation dial to almost 700 meters to have the scope and iron sights line up. The reticle is then in the lower third of the field of view. When I compare aiming though the barrel and through the iron sights, they are both on target. Any explanation?

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Brian, I see your point. I don't expect spot on interchangeability between rifles but the "no letter" block duv44 was really off target, way too high. It almost makes me think the rail is pointing upwards.

gergnotwen said:

This is why individual scope mounts were matched to a specific rifle and numbered. There are small variations, however you can re-zero the elevation and windage for a given rifle as excerpted from some old publication I found a while back. Don't expect a scope mount, especially a repro to hold zero from one rifle to another...

Click to expand...

I understand this part. There is no doubt machining tolerances preclude simple switching between rifles and still expecting to be on target. But this wasn't my point, I'm not concerned about being a little bit off target, I'm talking about the scope pointing 4 feet too high at 200 yards with the reticle centered in the field of view. I'm inclined to say I would have the exact same problem with an original mount which I confirmed by repeating the same test with another scope rig. Same results.

gergnotwen said:

"Turret adjustment was simple. Each turret has three locking screws. To zero the rifle, one first removed the screws from one turret, either elevation or windage."

Click to expand...

The adjustments mentioned in the instructions only pertain to zeroing the windage dial and setting the elevation knob to the correct distance after sighting it in. It will not fix the problem where the scope points upwards with the horizontal cross hair being in the lower third of the lens system for being on target at 200 yards, when really it should be centered.

Does anybody know if scope mounts were hand fitted to their rifles to ensure scope axis and barrel would run parallel?

I suspect they were all hand fitted to their rifle, taking into consideration the centering of the recticle too. The earlier scope rigs would also have the scope numbered to the mount etc.

Sounds like you may have had one extreme of the spec on the rifle dovetail and the other extreme on the mount...resulting in what you have described.


Brian

Thanks Brian, I think you're correct. I took measurements of the rails on all my G/K43 and one rifle (the G43 that shows the strange scope elevation) has a taller rail than the other ones. It's only 1 hundredth of an inch but small changes have large impact if it involves a 60 degree dovetail. I guess I'll have to play Waffenmeister and hand fit the mount to the rifle. Let's get out diamond file and scraping bar! I will let you know if my plan worked.

I have hand fitted several of Numrich's ZF41 rear sight rails to my K98's, therefore I have a good idea how to tackle the ZF4 mount. It sucks getting older and being unable to focus on target, front sight and rear sight simultaneously.

Thanks to everybody for their input.

I have seen with repro mounts where the scope cradle is not parallel to the mounting rail on the mount, and also you need to make sure that the scope is fitting correctly into the locating ring on the front cradle of the scope mount. If the male locating ring on the front of the mount is bigger than the female locating ring on the scope then the front of the scope will elevated, causing the scope to point up in the air, and the scope will probably shift when firing the rifle.
Titan

Titan said:

I have seen with repro mounts where the scope cradle is not parallel to the mounting rail on the mount, and also you need to make sure that the scope is fitting correctly into the locating ring on the front cradle of the scope mount. If the male locating ring on the front of the mount is bigger than the female locating ring on the scope then the front of the scope will elevated, causing the scope to point up in the air, and the scope will probably shift when firing the rifle.
Titan

Click to expand...

I agree with you on the requirement for parallelism. The reason for having the indexing hole on the original mounts was to provide the machinist with a reference plane for all subsequent milling and turning operations. I checked the engagement notch and ring and they fit as intended. The reason I started the thread was my observation that the rig was almost dead on aligned with the iron sights on two of my rifles -without any modifications or turning knobs etc., just switching back and forth between the rifles- and pointed upwards on my third rifle.

The ZF4 elevation mechanism is different from conventional scopes. Conventional scopes have reticles that don't move. They stay centered in the field of view. Misalignment is compensated for by moving lenses around internally with the help of the windage and elevation knobs. The ZF4 scope only uses one movable lens, for windage compensation. For elevation control, the ZF4 reticle is mounted to a spring loaded, hinged diving board. The elevation knob has a cam lobe that presses down on the diving board against the spring force, allowing the reticle to move up and down. So, if you shoot long distance, the elevation knob will lower the reticle below the centerline of the ZF4 scope to make the muzzle point up when taking aim.

That also means, at close range the center of the barrel, the iron sights and the ZF4 with its reticle put in dead center should all pretty much converge on the same target point. That wasn't the case here, the ZF4 pointed way up. After eliminating all other possible causes, I hand fitted the scope mount and now it looks fine. I have hand load a couple boxes of IMR4064/150gr Hornady and will take the rifle to the range this weekend for further testing and refinement.