.....@ 7000' the atmosphere is 0.77 sea level. So how many pumps does it take to equal 10 pumps @ 0 elevation?
Simple math says 13. I'm guessing, however, that my premise - you can simply pump more times because the valve will have less pressure also means that the pump stroke efficiencies will drop off at different rates per stroke.
Any PV = nRT guys out there?
[Avogadro Was An Airgun]