control valve question

[stargrazer]

I was wanting to install a needle valve at the end of the hose where it connects into the Hatsan filler unit so I could control the airflow when I turn on the scuba tank to fill the air tank on my AT 44S-10. I noticed when I turn on the scuba tank all the pressure from the tank hits the tank on the gun all at once. At least that's what it seams like to me. I have had no luck finding a 1/8 npt needle valve to accomplish this.
Does it make sense as to what I am trying to describe?
Any ideas? Am I wrong about the pressure hitting the guns tank?
It just seems to me that there is no pressure control from the scuba tank to the guns air tank.

[rsterne]

Usually if you turn on the SCUBA tank valve very slowly (just "crack" it) you can fill your gun slowly.... If you do manage to find a needle valve to put at the end of the hose that is rated for the pressure, then you will also need a bleed valve between it and the gun, or you will have to remember to do things in the proper order to safely remove the hose from the gun....

Bob

[stargrazer]

Thanks Bob.
Sounds like I don't need the needle valve so long as I crack open the tank slowly. The Hatsan filler has a bleed valve on it but it would be on the wrong side of the pressure, unless I have the needle valve wide open when I shut off the tank.
Thanks very much for your input.

[Voltar1]

Try this, leave the bleed open, slowly open scba tank valve until air starts hissing. Close it and try again to learn where the valve opens. With air lightly hissing close bleeder valve and open tank valve ever so slightly to fill gun. Observe pressure climbing at a slow controlled rate. When at desired pressure close tank valve, bleed off and disconnect. When I fill my guns my hand never leaves the tank valve.
One of my tanks has a miserable valve so I use a 1/4" male,female needle valve to control fill rate. It is sst and 10,000 psi rated.

Cheers

[stargrazer]

Thanks Voltar1.
I shall give that a try.