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Peska · Member

I'm kind of new to the game, and don't own a CO2 gun of any sort.
A springer, couple of pump-ups is all. I've been tempted to buy a CO2 pistol. Looking at either the Benjamin EB22 or the Crosman 2240.
My concern is this: Won't every single shot from a CO2 gun be lower in
velocity from the shot preceding, or is it regulated somehow to give consistent velocity until it just can't any more?
And my other question is, once it reaches the point of velocity too low to be
even halfway useful, how much gas is still in the cylinder which will be wasted?
How do you CO2 guys deal with this?
Thanks in advance for any and all input.
Cliff

AirGunEric · Site Admin

Yes, every Co2 shot taken lowers the reservoir capacity of the Co2. This does not necessarily reduce the velocity of each succeeding shot however as the expansion rate of the Co2 from liquid to gas is always the same. What does happen is that the last 15% or so of shots from a Co2 reservoir do lose power/velocity as the reservoir itself has no liquid Co2 left that can expand and you are only dealing with gaseous Co2 pressure and whatever it sits at depending on the temperature. This means that about 80% of the shots will be consistent, 20% then diminishing increasingly shot-by-shot. Also, the bigger the tank- obviously- the longer it will take before hitting that bottom 20%. A 12g caplet is problematic because of this, but a bulk-filled Co2 tank (i.e. 12oz) will supply hundreds of shots before falling off in velocity- and if you can shut off the gas flow and re-fill the tank, you will only have to refill the depleted 80%.

Peska · Member

Thanks for that reply, Eric. I believe I've got a little better understanding
now. If I'm correct, it means that if, for example, a CO2 bottle had the
capacity to get 100 rounds out of my pistol, the first 80 or so would be
pretty consistent, and then the last 20 would drop off rapidly. Is that correct?
If so, I feel a little better about buying a CO2 gun.
Then, the next question is, which one? heh heh.
How do you guys feel about the two I mentioned? I like the sturdy build of
the EB22 by Benjamin (I already have the HB22) and I have heard that the
Crosman 2240 has a plastic receiver which puts me off a little. (That's probably why it's so much cheaper than the Benjamin). However, I really
like the looks of the 2240 and from what I've read, it's very modification
friendly.
What do you guys think?
Thanks for your thoughts.

Cliff

OH, and one other thing.
When you put a CO2 powerlet into the gun, do you need to use it up
quickly? I mean, can I put one in and leave it for a couple of weeks? Or,
will the gas leak out?
Thanks again.

Alstone · Moderator & Site Supporter

Hi Peska
I have a few Co2 guns, pistols and rifles and all run on 12g Powerlet's, as Eris says 80% of shots should be reasonably consistant, but if you fire rapidly the expanding Co2 act's like a refrigerant in a freezer and cools down the metal on the gun, and consequently the power drops until the gun warms up, shooting single shots with 15 seconds between shots will keep the power consistant.

As for leaving the Powerlet in the gun, it does depend on the type on seal system used on the gun, if the powerlet is pressed down on to a flat washer to seal it then don't leave it in for longer than a week, as the seal may deform and not seal the next powerlet you use, if the seal is an O ring which seals around the neck of the powerlet then you can leave it in for a lot longer, some type of rifles use two Powerlets at a time and because these are sealed in a tube they can be left for months with no problems.

Al

Peska · Member

Thanks Al,

Appreciate the input. I feel a little better about the possibility of
buying a CO2 gun now. I'm on Guam, so the temperature problem
should be lessened a bit if I take my time between shots.
It's not exactly like we have a winter here, heh heh.
Thanks again,
Cliff