using stirrup pump

[rapidresponse1]

im not the best with how these work say i have 100 in my gun and i connect gauge and start filling does it not start filling till i get past 100 in the first place if that makes any sense

[rapidresponse1]

any one with views on this please

[JonRA]

I think that's how it works - you have to reach the pressure in the cylinder before it will overcome it and start to fill it. I've been using a pump (with dry-pac) for a while now and much prefer it to having a scuba cylinder cluttering up the house. Mind you, I only fill at home and that has to do me.

[ashf9999]

As mentioned above, you need to ‘match’ the existing pressure. The ease of doing so depends on the pump you’re using (a bog standard would take more than a Hills, for example), the bore/length of the hose (dead volume), condition of pump seals, any slight leaks with the probe etc and the starting pressure (so the higher the initial pressure the more it takes to get the gauge moving).

I must admit I primarily use a cylinder these days, but take the Hills for topping-up if need be. A shoulder injury a few years back means I don’t really like using the pump if I can get away without.

[Shed tuner]

yeah, but it should only take 4-6 strokes to get up to 100 BAR, and then depending on your cylinder volume, roughly 1-2 strokes per BAR to top up. Smaller cylinders are OK with pumps, large ones are a bit tedious...

[angrybear]

It's really simple, if the gun has 100bar in it then to fill it further you need over 100bar in the hose to push open the valve, so first you have to pump the hose full to 100 bar.

Once the hose pressure is equal, the next few pumps will push the hose pressure higher than the gun pressure & that extra will push the gun valve open,
as soon as the pressure in the hose & the gun are equal a tiny little spring inside the valve will close it,
the next pump stroke again makes the hose pressure higher and it all happens again, & so on with every stroke of pump, until both the hose & the rifle contain the max pressure.

You then vent at the pump so the pressure in the hose drops & the spring & internal pressure in the gun holds the valve closed to stop the air inside the gun escaping.

If you have a scuba cyl to fill the gun, the higher pressure in the cyl will push the gun valve open and will fill the gun in one push,
but as the cyl empties there will come a point where the cyl contains less pressure than the rifle max at which point the two pressures will equalise and that's it until the cyl gets refilled.

[rapidresponse1]

many thanks for help chaps it does not take much to confuse me

[jjjohn]

A tip I found helpful is this
don't use the pump as a ''pump'' if you will,use it as a drop down thing,i.e let your weight lower the plunger dont try to use arms only.
Once you get the knack its far easier that people make out

[Neil54]

You need to fill to 200bar if your only firing a few shots. Depending on the gun you may only need to fill from 100 to 120bar.

[jjjohn]

200 bar gets me about 80 nice shots in .22 with my GX40.

[rapidresponse1]

many thanks