I get approx. 65-70 good shots on one Crosman CO2 in my CR600W. Only got around 60-65 shots when I used Umarex Co2.
Try to never leave CO2 in overnight. Only airgun I consistently left it in over a few days was an older one that used 88 gm. CO2. It later developed seal issues.
So my advice. if you are comfortable replacing seal & valves, maybe leave CO2 in you airguns. If not, maybe far less expensive in the long run to just remove CO2 at the end of each day. CO2 (esp. 12 gm. cartridges) are cheap, usually less than $1. Airgun repairs are not.
I have CO2 guns that I have used for many years without any seal or valve issues. I put a drop of pellgun oil on the top of each cylinder before I install them, and remove them as soon as I'm done shooting.
This system works for me. Others may have their own system.
Most of my CO2 pistols are newer. They may have made the seals tougher on older guns to withstand leaving CO2 in longer.
I don't think the newer CO2 airguns are designed to have CO2 left in them for any period of time.
I have bought a couple of vintage airguns that came to me with CO2 already installed. The airgun worked well for the remainder of the CO2, but valve/seals did not work/leaked badly, the very next time I installed CO2. Shipping time was probably 1-2 weeks. Go figure.
Would like to hear from people that leave CO2 in the more expensive newer airguns, for extended periods of time.
For example the Legends Lever Action uses 2 - 12 gm. CO2 that give you around 90 shots. I understand Umarex does not stock parts for these guns & doesn't even have a parts diagram available. They consider them "non-repairable", i.e. disposable. I for one, would not be happy with myself, if I ruined the seals on a $300 airgun, because I was too cheap, to remove $1.50 worth of CO2 each time I finished shooting.
Airguns with CO2 in the magazine don't apply, as it is a lot less expensive to just replace the mag. if the seals go.
