Forget everything you knew about springers and their inherent problems.
The forums are full of people asking how tune the "thangs", the "sqeaks", the vibration, the recoil and the hold sensitivity out of their springers. Tars, guides, molys, shims, etc...
Well it seems like Diana had already the "recipe" some 50 years ago!
My Diana 66 just came back from Mike - the talented and ethusiastic airgunner who has repaired my 4th Giss airgun for free. The pistols felt good but this my first Giss rifle.
Well after changing BOTH deteriorating piston seals, breach seal, a worn "sharnier" washer in the barrel pivot point and lubing everything properly I have to say that this airgun is built like a vault, the mechanism cocks like a swiss watch and the trigger breaks like glass!
Enough with the clichés though. When you pull the trigger after a short first stage the second stage comes repeatedly well defined to break in the end crisp exactly when expected.
Then comes the firing cycle: You hear a short crackling sound and then you see a hole in the target.
Nothing else! No vibration no recoil - not a thing. It feels like a PCP, or better , as if you didn't fire it yet. The target image is always visible in the small peep apperture and the best of all:
The target has just one hole, benched @ 10 meters, even with cheap H&N Sport 8.18grain pellets!
Here are some photos: