Just opened up the 850 valve using a pair of split ring pliers. The threads are sealed to ensure the valve does not leak. I'm using RTV to reseal while playing with the spring. Not sure how this will do for holding the pressures but its just a test. But be very careful while taking the cover off...

The replacement spring has not been tested, so until then it remains unspec'd... its a generic spring out of my spring scrap box. I did spec out the factory spring which was small in dia and was slightly curved.

This is the valve off my .22. Currently before the mod with the new hammer spring its shooting 780 with CP's using HPA. Will try to hit mid 800's by altering the valve spring.

The snag here is you cannot access the valve with the factory stock in place, so I will be testing with the stock off.

Rich is already shipping the first of the AirSource to 1/8" NPT adapters to Henry!! We are in business gents!! He's got to buy some brass hex stock to make more of them and they'll be available sometime around Sept 24th... $17 each with a 1/8" quick fill nipple. My RTV job is holding air but haven't had time to test - hopefully I'll be able to get it all apart if the numbers aren't good...
I also mentioned to him the AirSource to Paintball adapter. If you guys want a gauge then a 1/8" NPT hole might be drilled on the side and plugged for a gauge.

I like the idea of a pre-drilled valve hole too.I guess CO2's always at 850psi when charged and falls off pretty quick once the liquid is gone? In which case, the guage does not have to be too fancy, just a "now you have gas / now you don't" kinda thing.

Here's what I've plan to run my bulk-fill.

I'm getting couple small CO2 cylinders so I can reuse the forearm handel. I have my eyes set on the 3.5 oz cylinder manufactured by Catalina. It's light-weight and it has the correct length to be still fit inside the compartment. It's measured 2" in OD, 5.33" in length and around 0.45lb. The 88g Air Source bottle is 1.5" in OD, 8" in length and around 1 lb.

I'll also get a a HPA tank to run a remote setup. This will be used when the temperature going below the normal CO2 operating range. So, I can still enjoying shooting after during autumn and winter time.

I'll do a little review once I received the adapter. But from the picture, it looks very promising. Unlike the one Mac1 sells, this on has the hex nut so you can use a socket to put it in and remove it.

$17 each with a 1/8" quick fill nipple from Rich. This is a great deal!!!

I decreased the spring force at full deflection by 10% but added some variables by increasing the OD to .5" and wire thickness of the spring to .041 but shortening it to 1.375" rather than 1.6". Its a much more stable and less prone to buckling but I miscalculated the spring force and it actually dropped the velocity down to 760 with HPA. All I have is deflection load data based on when the spring is fully deflected but I think the first 30% of deflection is the value needed. More springs coming from McM/C and more testing... The SD on this new spring was much tighter.

Thanks for keeping us updated Ken. well at least you know what direction it's taken. So it looks like the initial force required to compress the spring has increased causing a smaller open time window?
For mine, I'm almost tempted to order a whole new valve from UMAREX, just because both the valve spring and the valve stem it's self have 2 part #'s one for Europe and one for "export" I'm still thinking that mine is an import and the USA valve would work better for it.
You know what, I'm going to do it. I'll let you know how it goes. ..... just got off the phone, they have sold out of 850's!
Well he has one left and it's in .177. Anyhow I ordered me a new valve, we'll see how it goes.

 

.