air pressure

I have a hozelock pump action pressure spray bottle. I have noticed that as the pressure inside the bottle increases the further it fires the water. When it is under high pressure ( when it gets hard to pump more air in ) it will spray about 6 metres. I was wondering wat the pressure to distance ratio would be and how to calculate it. Also what would the pressure be inside the bottle when it is under high pressure. The tube inside the bottle is 1/4 inch inside diameter. Does the size of the tube affect the distance. If it was 1/2" would it go half the distance under the same pressure.

hope u can help