Is there any way to fill an airgun it with a single stroke of a hand pump?

Lets calculate:

Atmospheric pressure at sea level is about 14.7 psi.

2 Atmospheres means twice 14.7 psi or 29.4 psi.

If you take any size piston in a 12" long cylinder and you push it in 6" you halve the air volume and therefore double the pressure.

We have a rifle that needs 300 PSI in a 1/2" x 6" chamber.

1/2" x 6" is about 1.25 cu in.

300 PSI/14.7 = 20 Atmospheres.

IOW We need a 20:1 compression ratio with a final volume of 1.25 cu in.

Lets say that we can supply 150 pounds of force to the pump whose piston is 1 sq in.

(A car engine has about 150 PSI or so)

If we push our 1" piston a closed cylinder we can achieve 150 psi.

OK We are at 10 Atmospheres, half way to 20 Atmospheres.

We need to compress 12.5 cu in into 1.25 cu in. to get 300 psi.

If we take the 150 PSI and push a free floating 1/2 sq in piston (300 psi) in a ~12.5 cu in cylinder, we would reach our goal.

I calculate that we need about a 60" cylinder to achieve 300 psi.

Are my calculations correct?

BoyntonStu

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