Haenel 311 Sight and a Small Problem After Reassembling the Rifle

I had disassembled the Haenel 311 sight a while back and finally found the time to reassemble it. There was a lot of slop in the sight...

The flat plate that covers the guts had a serious dish.

Here's a view after a quick rub on the surface plate against some sandpaper. I worked it until that center section was flat.

I pressed the knobs back in with their balls and springs.

Clean and ready for reassembly...

Except that the sight had a problem in that the piece that holds the iris was too thick now. Which makes no sense as I didn't take any material off of the housing...but it explains why the plate was dished...

So I lapped it until it worked smoothly...you can see there's no visible gap.

Anyway, the rifle was sold to me with the problem that it wouldn't cock reliably...so I reassembled it not finding anything obviously wrong.

Just as on the 310, the surfaces that the spring contacted were rough.

So more lapping against sandpaper on the surface plate (a separate plate than the one I use for measurements, thank you very much...)

Still a few gouges but mostly flat...

Then I polished them.

I aligned the piston seal screw lockscrew hole...

It seems to stick up a bit proud compared to the 310...hmmm....

Anyway I reassembled it easily and it seemed to work fine...until I there were several times when it wouldn't catch. It seems to happen randomly...so I have to take it apart again.