CO2 variations

[short-carabine]

I was chronoing a couple of CO2 pistols and noted that pistols with a direct CO2 cap to valve seal fit have a marked tendency to show a gradual decrease in FPS, while the Crosman Mk1 where the CO2 is released into the grip shows virtually no FPS variation until the CO2 runs out. Anyone else noticed this sort of thing?

[richierich]

Semi-auto pistols will exhibit this behavior more as the CO2 capsule cools after every shot. If it's left for 30 seconds between shots, there is less of a variance but still noticeable.

The effect is made worse in the colder months as the temperature slows the co2's transition from liquid to gas, meaning a worse velocity drop, and reduced shot count.

[short-carabine]

Semi-auto pistols will exhibit this behavior more as the CO2 capsule cools after every shot. If it's left for 30 seconds between shots, there is less of a variance but still noticeable.

The effect is made worse in the colder months as the temperature slows the co2's transition from liquid to gas, meaning a worse velocity drop, and reduced shot count.

Hi Richie I have also noticed the same with single shot CO2s where the cap goes direct to the valve. My thought is that the system in the Crosman Mk1 is somehow more efficient. I think I will have to try a spot of Chronoing with my Zastava and 600 which operate on a similar principle to see if the FPS variation is minor in comparison with variations on a "cap to valve" direct system. I was actually shooting the Mk 1 on a basis of rapid reload. Then again, I may just have a superb example