co2 pressure question (Hammerli 850 AirMagnum)

[d3vnull]

I am looking at the Hammerli 850 AirMagnum. The .177 is listed at around 760 fps and the .22 at around 655 fps (PyramydAir). A couple of related questions:

1. Any idea what temperature/pressure those specs are based on?

2. Any idea what optimal pressure for this rifle is without valve lock-up on the stock hammer spring?

3. Any idea how high you can go with pressure without valve lock-up on the stock spring?

 

[crittahitta]

Are you planning on converting to high pressure air?

 

[scubajeeper]

If you are talking about keeping it on CO2 there won't be any problem. If you convert it to HPA, I would suggest a Dominator spring or a Rotek spring. I don't know how much pressure the stock spring can handle but my reg is set at 1850 and it will definitely valve lock at that pressure.

 

[Coldair]

If you are talking about keeping it on CO2 there won't be any problem. If you convert it to HPA, I would suggest a Dominator spring or a Rotek spring. I don't know how much pressure the stock spring can handle but my reg is set at 1850 and it will definitely valve lock at that pressure.

Did you do anything to increase the safety factor? I thought the safe range for HPA conversions were between 850 and 1100psi.



CA

 

[d3vnull]

I'm planning on staying with co2. However, being in Texas temperatures can get higher than 100 degrees which puts the pressure pretty high on co2. I'm doing some research on an inline co2 regulator on a 9 oz co2 bottle, and was just curious what pressure most co2 rifles are optimized for.

 

[Coldair]

I'm planning on staying with co2. However, being in Texas temperatures can get higher than 100 degrees which puts the pressure pretty high on co2. I'm doing some research on an inline co2 regulator on a 9 oz co2 bottle, and was just curious what pressure most co2 rifles are optimized for.

I wouldn't even bother to waste the time and money to regulate Co2 because it should be just fine as is.

Good news is that you live in a hotter climate which is perfect for Co2.

850 to 1100psi are the typical Co2 pressures in airguns depending on temperature.

CA

 

[scubajeeper]

If you are talking about keeping it on CO2 there won't be any problem. If you convert it to HPA, I would suggest a Dominator spring or a Rotek spring. I don't know how much pressure the stock spring can handle but my reg is set at 1850 and it will definitely valve lock at that pressure.

Did you do anything to increase the safety factor? I thought the safe range for HPA conversions were between 850 and 1100psi.



CA

Co2 runs at that pressure. To get an 850 to shoot at a decent velocity, you have to run them that high (1800 or so). It's what you would get if you were to buy one of the 850 store's guns that Roald used to build. I've got over 6 thousand rounds through my gun with zero issues, it's really a great little gun.

 

[d3vnull]

I emailed Roald. He recommended holding the co2 pressure at 850 psi (pressure at 75 degrees F) in order to achieve stock foot pounds of energy. I think ~12 foot pounds is enough for my needs. Since the regulator will be custom I will have it adjustable up to 1100 psi just to play with the pressure. That seems to be valve lock-up pressure with the stock hammer spring according to some reviews. 

I am going to tether it to a 20oz co2 bottle. This is a long-term project since I am still working on a handicap benchrest. But you never know, someone may entice me with a great black Friday sale

Long-term I'd like to mount this on my wheelchair like this guy did so I can be mobile:

https://www.handihelp.net/2093/index.html

Thanks for everyone's input!