Yes, the PCP will use more air than the springer, depending on various factors probably twice as much. One reason why they are usually louder.
Holder of nine NSRA gold medals
Yes, the PCP will use more air than the springer, depending on various factors probably twice as much. One reason why they are usually louder.
www.shebbearshooters.co.uk. Ask for Rich and try the coffee
Registered User
If you put a balloon over the barrel of your PCP, collect one shot's worth of air in it, then measure the volume by displacing water in a measuring jug you won't be too far out. From memory it is usually somewhere between 150 and 300 cc, depending on the gun, the power etc.
Alan
Holder of nine NSRA gold medals
That's a little high as an estimate, but you said it's from memory.
The last rifle I tested using the balloon method was running a bit warm power-wise and was using 140cc per shot.
www.shebbearshooters.co.uk. Ask for Rich and try the coffee
Registered User
It's not hard to work out.
I fill my FAC rapid to 210 bar, 400cc bottle, so 210 x 0.4 = 84ltrs of air
I get 55(ish) full power shots before they drop off at 120 bar, 120 x 0.4 = 48ltr
84 - 48 = 36ltrs used
55/36 = .654
so 654cc's per shot .25 at 42ftlb
or there abouts.
.177 is least economic with air, .25 most economic.
Is your gun regulated or not? I'm guessing it is.Originally Posted by angrybear
I've read a rule before of about 1cc to 0.5cc of air consumption per ft/lbs in a regulated gun so that must be wrong?
Edit:that is plenum volume not air.
Last edited by arnie2b; 24-03-2019 at 10:06 AM.
Banned
When we did the calculations using digital gauges on the Steyr .177 running at about 11.5 ft-lb it was using about 200cc at atmospheric pressure. (From memory)
Registered User
No it's fast flow.
Registered User
Reading the replies & comments with interest. I like the idea of catching the air in a baloon to measure the resultant volume. Might try a modification to that with a plastic bag as being less constrictive it wont exert much pressure on the air inside thus reducing its volume a fraction.
Rich mentioned that a PCP might use a bit more air than a springer.....is this because the pressure increase with a springer is more efficient at getting the pellet moving? I suppose the pressure build up with a springer is much more gradual than with a PCP. Then if a PCP is a bit louder is this 'wasted air' expanding / venting after the pellets left the barrel, if so why isn't the dose of air reduced a bit, or is this what a regulated PCP is?
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