Kassnar were branded Jap scopes probably done by Hakko in the budget offerings. Same as Optimas in so many ways. Branded so features and glass taken from a list to hit the target market price that the importer wanted.
Yes, they are correct for vintage 1980's rifles. They are just about robust enough for springers. Glass varied but generally average especially once seen through the over hype. Being selective then many a Tasco are better, not later ones and not all. 80's Optomas were good though in the last years were showing their age, cost cutting.
Seen that Kassnar and its a big scope. Value possibly £100 and thats being generous.
The mid 80's fashion for huge front objectives was always going to be disappointing. These huge scopes were a lump and in truth the optics weren't that good. The smaller scopes were often brighter, lighter and didn't throw the balance of the rifles they were going on. Dusk these budget scopes failed as the coatings and glass, plus a lot of masking because of poor edge definition, just didn't match the expectations. Even Tasco failed when going big. Just not enough money in them to work.
Circa 1992 and Simmons blew the budget market out of the water with their White Tailed Classic. Tasco with their Euro Class and TR range. Then it was down hill all the way.
Leupold were still king. Bausch and Lomb were Jap class. Both could be found with parallax for Air Rifle ranges. More and it was European and very high ticket prices and the wrong parallax
My view is don't pay over the odds for Kassnar.
Mint scopes from the 80's are worth a huge premium to be put on mint rifles. For anything well used then don't pay much. Very nice then a fair price, but there should be one set of scope mount marks and best if the mounts are included and correct. Best if mounts are both in the right place and match the rifle too.