Grooved ES 340b Rear Sight

Rather than a new thread I think my question would fit here. I have had several es350b rifles and the grooves of the receiver and the barrel were extremely close in width on a given rifle. Close enough that the rear sight of one would fit the receiver grooves of that particular rifle. Always some slight variation on the widths between the rifles so one particular sight may or may not fit on a different rifle but thats not the reason of my post. No point of mounting the sight on the receiver anyway. Usually..

But my grooved barrel es340b has receiver grooves and barrel grooves of very different widths. The barrel grooves measure slightly over 11mm where the receiver grooves measure slightly over 12mm. A problem would arise when mounting a fitted diopter sight or in my case using fitted scope mounts from a different Mauser smallbore. The grooves are too wide to permit interchange. I have not found another Mauser with 12mm spacing on the receiver. For those that have the grooved es340b rifles have you found this difference? Or on any “ b” model?

I will measure on mine and let you know.

This is why I was inquiring about how the sight installed. On the es340b, there are cuts in the grooves of the barrel, the same as the es350b, but on this rifle, I could not see any cuts.

If nothing else, I will have another sample to take apart and measure for us.

Was more than I wanted to pay with the stock issues, but I suppose for what it is, it will be a good shop sample for reference.