Wasn’t it Cardew who experimented with a spring gun using nitrogen rather than air, and found the power considerably down due to the lack of dieseling? Another factor regarding energy comparisons.....
It was indeed.
According to cardew he got an overall efficiency of 5% pumping up a pneumatic
He got 25-35% efficiency from springers. So pneumatics c six times less efficient , about where Geezer and Tom Gaylord had it.