Wow, that is a
REALLY good price for a FP-AG; I spent ages looking for one on this side of the pond and never got anywhere close to this (ended up buying in the US through family...)
For those just starting to look into these aperture sights, a note to point out that 2 different sights are linked in the posts above: AG and GR versions of the Williams FP ("foolproof") series. The difference is how high (and low) they can be adjusted so depending on your specific rifle and/or typical shooting range, it might be important to chose the right one.
The
FP-GR has a longer height arm which means it is more likely to foul the left stock when it is lowered for adjustment to shorter ranges. A relief cut into the stock to accommodate this should at least partially sort it out but is of course a permanent mod. (at least at my level of woodworking "unskill"...) Or, alternatively, a riser under the foresight...
The
FP-AG's shorter height arm should not reach most stocks and I believe its smaller adjustment range should be sufficient for typical airgun ranges using the Weihrauch OEM front sight.
To give a rough idea, here is mine on my HW50s (UK 99), zero'ed at 10 meters.
View attachment 917318
With my sight base, I have at least 5 milradian upwards adjustment available to me which is more than enough for me and my rifles.
All that said, these are not sights I would want to be constantly adjusting as, even with the "Target Knobs" option, you still need 2 sizes of screwdriver to change elevation ("only" 1 for windage). They're brilliant for either known range paper punching or fit and forget PBR-based adjustment chosen to your rifle/pellet/garden/range/quarry combination.
'got a bit carried away rambling there, sorry... Hope it helps,