Best air rifle back in 1950'/60's ?

[Benelli B76]

I suspect that it may have been due to the 6ft/lbs limit on air pistols & that a CO2 pistol could easily be made to exceed that.
Thirty-odd years ago, someone I worked with asked me to take a look at a pistol he had because it wasn't working properly, which turned out to be a Crossman .22 CO2 pistol. I can't remember the model number, but it had a 10 shot (if memory serves) tube magazine above the barrel.
Anyway, I found & fixed the problem, and out of curiosity I put it through my chronograph, discovering that with Eley Wasps it was turning out over 10ft/lbs ! Not only that, but I also found that a simple adjustment could make it fully automatic, though it would use a whole CO2 bulb for the 10 shots in the magazine.
Before I tested the pistol I'd been somewhat dubious about the owner's claim that he used it to kill rabbits in his vegetable patch, but clearly the gun had the power to do that.

Never heard of a 6ft limit on air pistols in those days nor a 12 ft lb limit on air rifles either. In the USA, some kids got the Crosman 600 a bad reputation due to its 10 shot semi auto capability. I distinctly remember a newspaper article in UK running on how deadly these pistols could be. Typical hype to wind up the anti gun population. I was a teenager at the time living in Luton, had an old boy mate who had loads of firearms including a double barrel .410 pistol. He quickly got a licence for a Crosman 600. I remember he used to fill the pellets with Polyfilla to add weight for some reason.

Baz