Several quick questions about HPA.

[tucson.az.jbreen]

Bottle with preset 850 psi preset reg.
On/off asa, macro line straight to the valve.

Question one: with high pressure air do I need a gas through grip (expansion chamber)? With hpa does that make a difference?

Question two: do I need or want a regulator between the bottle and the valve?


I ask these questions because my x valve is kind of erratic on the fps. Like between 265 and 290.

The same bottle on the mini mag is very consistent. The minimag is set up for remote use only.

[Mondoatx]

Question one: with high pressure air do I need a gas through grip (expansion chamber)? With hpa does that make a difference?

No, an expansion chamber is not needed with HPA. Compressed air does not liquefy at the pressure found in a bottle... so no need to give it a place to expand. I suppose technically it couldn't hurt anything though... all it would do is create a longer path for the air to travel between your bottle and your valve.

Question two: do I need or want a regulator between the bottle and the valve?

No. Triple regulating your mag will starve it of air. There is a reg on the bottle (preset to 850) and another on the A.I.R. Valve... a third one will generally cause shootdown in rapid fire (that is what everyone says anyways... I tried it back in the 90s with an inline reg and that is what happened to me... valve would not recharge fast enough during rapid fire).

I ask these questions because my x valve is kind of erratic on the fps. Like between 265 and 290.

Not sure what would cause this... but it does seem like a big jump from shot to shot. When was the last time the seals on the gun were changed out? Also, let's see if someone else chimes in. Maybe they can be more specific regarding which seal(s) to change out.

The same bottle on the mini mag is very consistent. The minimag is set up for remote use only.

This seems to indicate some difference between the internals of the two guns... and not an issue with the bottle reg. When was the last time the seals were changed out in 1 gun VS the other?

Hope this helps.

Mondoatx

[Mondoatx]

Oh, and the remote shouldn't make a difference either... you can try putting it on the one with the poor shot to shot consistency to see what happens... but I don't see how running a remote on HPA would effect the gun's chrono consistency...

Mondoatx

[athomas]

Paint can cause inconsistent velocity, especially when it isn't properly matched for the barrel. If the same paint is used for both guns/valves shooting with the same barrels, then the inconsistency is in the valve. Make sure there isn't any dirt in the regulator piston assembly area. That can affect the automag regulator's ability to adjust minor changes in pressure/velocity.