When to refill my PCP?

[BigDuncs]

I want to find out the optimum refill time for my pneumatics. So I -

1) get the chrono and get a safe backstop
2) refill the PCP
3) shoot and note velocity

Then what?

Shoot 5 shots and leave to let the compressed air temperature to stabilise?
Fire only one shot per minute to simulate more realistic shooting conditions (rather than one shot every 10 seconds or so)?
Measure the vel of every pellet or to save time, every 5 or so.

When do you know it is time to refill based on these results. When the initial vel is reduced by 10%?

All opinions greatly valued! Hope that this doesn't sound too dumb a question.

[roughshooter]

Gun makers usually quote '' n full power shots'' per, say, 200 bar fill. Treat
this as a guide.

Backstop on floor, box of rags on top, paper and pen handy, load to said fill pressure, sit down and start shooting and recording. 100 shots,
Boring, but you'll propably find time spent writing it down, reloading etc
sufficient to allow any air system to keep cool (CO2 is different).

By doing it this way, you'll find the 'heart of fill' - a long number of shots
all very close, speedwise.

Say shots 1-15 all about 575 - 590fps (.22) then numbers 16 - 70 all 600 fps give or take a few fps, 71 onwards dropping into the 570's - 560's, you'll
know that 55 consistent shots are available. Refill slowly so you see the
start pressure in gun. If it's 120 bar, you'll have used 80 bar for 80 shots.

Refill to 185 bar, save wasting first 15 shots which were 'slow'. Check a few again. If shots speed still closely about 600 fps, job done. Put 50 pellets in a 35mm film can and when you've used them up, refill gun to 185 bar, put another 55 pellts in can and off you go.

Only way you can be certain that misses/fliers are your fault

HTH