Tuning RX-2 Recharge Process

[Colonel_Angus]

I have the Fox Racing Pump w/Gauge and all the parts to get air into it.

I charge it to between 22 and 25 bar and it releases a pffft when i disconnect unscrew the connector.

It's shooting 520 - 555 fps with Meisterkuglen and should be much higher.

I tested the barrel seal 10 yr. Old (Original) and it passes tissue test.

Is there anyway to keep the Pffft from loosing the air and what else should I check to get it back to being a tack driver? It's a 1" gun at 20 yds. now where it was one ragged hole.



D n Dallas

 

[Odoyle]

Aren't they 17bar/250psi max fill? 

Velocity may go down if over pressurized.

OOPS 22-26bar max double checked.

How are you measuring fill pressure reading is your measuring device accurate? 

It's a Schrader type valve you need to unscrew it fast and it will leak out some air.

 

[biohazardman]

I just looked at your pump online and Odoyle is correct it has a Schrader type valve so there is no way to stop a little from leaking out as you unscrew the pump. There is a pin in pump connector that holds the valve open so long as it is screwed in. So as he said unscrew it fast to lose less air. 

Some pumps use a lever affair that could reduce the air loss as it releases the valve much faster.

As for the accuracy problems have you ever cleaned your barrel?

 

[Odoyle]

If it's actually over pressurized and you dont even realize it your accuracy will get worse.

A good indicator is how much more difficult it gets to cock the gun. If shooting only 500fps it should be effortless to cock but difficult if its over pressurized.

You have the pump so tap the rear fill part of the gun with a pin or ice pick to vent some air out then chrony again.

 

[Colonel_Angus]

I just replaced the barrel with a new HW90 in .22 recharged and it's shooting 707 with Benji's in 14.3 GM =15.8fpe which is too low.

Cocking pressure is acceptable.

Any thoughts other than raise it to 26 release as fast as possible then chrony and release until perfect?

TIA

 

[coop709]

As a mountain biker, I am familiar with the Fox pump, when you disconnect the pump it is designed to release the Schrader valve before releasing the air in the connection to the atmosphere. The small amount of air that leaks out should be what is trapped inside the connector. To test this, disconnect it very slowly, as soon as you hear the air leak out, stop. If a large amount of air comes out and the ram is empty, you are losing pressure. If you get the same amount of air as your “regular” break in the connection, my thought is correct and you are not losing any in the ram. The volume of most Fox Shocks is very small so you cannot afford any leak when disconnecting the pump.