CO2 or CA ?

[rcmillerjr]

I'm sure this question has been beaten to death time and time again, and I apologize, but I am new to air guns. I am a pistol shooter, and would like to obtain an olympic quality air pistol. I see some used C02 guns on the market, and what I gather from all I've read that they are a thing of the past and compressed air is the thing now. But from what I see, a lot of the major records are still held by C02 guns. I don't need the latest up to date equipment as I am near 70 years old and could never hope to attain olympic status. Money is not an object, but I hate to waste it if I don't need to purchase the latest up to date equipment. Is there a major drawback to using CO2?? Any help would be greatly appreciated.

[Steve Swartz]

Some points to consider:

- I don't think you can make a strong case that CO2 is any more accurate than PCP. CO2 was the dominant technology back when the records were set. There are other factors in play that may explain the inability of today's shooters to break those records (scoring technology is somewhat less "forgiving" than manual scoring was, for one example).

- CO2 may have up front advantages in price initially, but the long term costs may run higher.

- The "hassle factor" may also be worth considering. Availability, scales, refrigerators, etc. etc. might factor in to your decision.

CO2 technology is certainly not "Dead" (especially at the club level) but I think you are correct that it is rapidly becoming a smaller and smaller minority at the national/international level. There must be reasons why the marketplace is turning away from this technology?

Steve

[superstring]

Here's an opinion from:

http://www.airgunsonly.com/frames.html

As you will see there are 2 other articles on the subject from the same site. From the home page look at the navigation bar on the left and select "Tech Tips". Note that these articles were written a few years back when Compressed Air hadn't reached the popularity it has today.

CO2 GAS vs. CYLINDER-AIR

There’s a lot of chat on this subject to-day and a lot of opinions…..Here’s mine…..

Today there is a particular trend towards the use of pressurized air instead of CO2. Let me say from the start that I am still a strong believer in CO2. I can give you a lot of reasons why CO2 is still better but I can’t give many in favor of air. For example, A CO2 pistol or rifle is usually cheaper in original cost than an air model, it is simpler inside and has less to go wrong…..no gauges or regulators to worry about. There is little problem having CO2 supply tanks filled, any fire extinguisher shop will do it and it doesn't cost a lot. Some SCUBA shops will require you to be a member of a dive club or have insurance before they will fill an air tank for you. Before you buy, check out the cost of a CO2 cylinder vs. the cost of a SCUBA tank and DIN adapter, Also check out the cost of a 200 BAR. handpump, you will see that CO2 filling is much cheaper than air. CO2 pressures that you will be working with are around 800psi……air pressures are around 3000psi. There are precautions to take with both but the dangers using air are much higher.

The argument in favor of air that the factories like to make is that the pressure of CO2 changes with temperature and air pressure does not. A lot of shooters have gotten a paranoia about it. If you look into this carefully you will find that it is technically correct but one would have to be shooting in under some very strange conditions before there would be a noticeable change of point of impact on the target due to temperature change in the cylinders. It can be shown, for example, that there is no noticeable change in the point of impact on the target over a temperature change of 15 degrees [from 55 to 70]. One is not likely to encounter this kind of change on a normal indoor range while he is shooting.

We have heard of shooters experiencing a noticeable change in point of impact for the first fifteen or twenty shots after changing cylinders or with the first shots on a warm rifle. [not so noticeable for pistol] It seems to be more pronounced on certain rifles. During the firing process CO2 tends to cool the pellet, chamber, bolt and other parts of the action. It is possible that there could be some velocity changes associated with this temperature change due to the length of time that it takes to "stabilize" the temperature of the mass. It would be more pronounced on a rifle due to the greater volume of gas used for each shot. Perhaps this is why CO2 was never accepted by the rifle shooters but was popular with the pistol shooter.

There is one advantage to air that should be considered, it is one that you never hear about and it may be the only good argument in favor of air, it has to do with barrel time. We are told that CO2 gas has a higher molecular coefficient of friction than does air. What this means is that when air is compressed and released it will spring back quickly because the molecules of air have little friction. When CO2 gas is compressed and released it springs back slowly because of the higher molecular friction. Another theory says that when air is released it simply has to expand…..when CO2 is released it has to “boil off” from liquid to become an expanding gas, the latter process is a slower one. If we translate this to an airgun situation it can be determined that the pellet acceleration in the barrel of an airgun will be faster than that in a CO2 gun…..even though the muzzle velocity is the same. The all-important barrel time in the airgun will be shorter and if the theory is correct, the airgun will be more “forgiving” than the CO2 gun. You may have noticed that when you fire a CO2 gun without a pellet the sound is sort of a “pop”, do the same with an airgun and there is definitely a sharper “crack”. This little-known feature of air is theoretically an advantage but it is probably a microscopically small one!!

Handpumps…… .They cost over 200 bucks and they will kill you!! Ever try to pump up a 200 BAR rifle cylinder?…….you could have a coronary!! The last thing in the world that you need before a match in an aerobic exercise!!! Another problem with handpumps is the possibility of moisture getting into the pistol. Pre-compressed air has not been in use long enough to tell yet but I predict that corrosion from moisture will eventually take place inside the aluminum cylinder presenting a major safety problem. I can forsee the necessity of inspecting the inside of the cylinders on a regular basis.

Obviously its my opinion that CO2 is still the best [at least for pistol]…..not convinced?….read the other two accompanying articles NOTES ON CO2 FILLING and NOTES ON AIR FILLING.

[dhurt]

I have experience with both modes and I would say I like the compressed air a little better than CO2 for the following reasons:
I once attended a winter match with my CO2 pistol, indoor range conditions were fair, but I had traveled to the match with my pistol in the trunk of my car. I was new to the CO2 technology, and I didn't realize cold CO2 doesn't work. I got lots of white, liquid CO2 spouting out my pistol. I had to borrow a pistol to shoot the match. Keep your CO2 warm and you are good to go.
I shot an outdoor match, once upon a time, where the outside temperature was in the mid-nineties. I did not realize high temps cause CO2 to put off more pressure. My gun "seized up" and I had to borrow a pistol to finish the match. I shot the same match the following year, and it was the same outdoor temps, so I rested the cylinder on a bag of ice, and I had no problems. Keep your CO2 cool and you are good to go.

All this being said, I think CO2 is pretty good if you know its limitations, and I would not be afraid to shoot an important match with CO2. Best regards, Dwaine.

[Bill177]

I have a Pardini K2 in Co2. I bought it that way new about five years ago. Beause:

I do not wish to deal with the problems of a scuba tank.
Co2 is a constant pressure - requiring no regulator.
A few less parts in the gun.
Less pressure means - to me - greater safety.
I only shoot at home - so I don't care what they have at "the range."
I get over a year of shooting on a fill of my 20# tank - for $14.

Check with www.pilkguns.com for a quality used Co2 air pistol. They represent a great value for the dollar. Resale isn't as good as a PCP, but at my age I could care less.

[tenex]

Several of us have just started AP in the last few years, I bought a PCP gun and a few others have CO2. We shoot indoors in the winter, so there doesn't seem to be any issues with extremly low or high temperatures.

I think the only real difference is in convenience. I like PCP because I can glance at the cylinder and see how much air is left. I also have a pump, so I'm never stranded but it's a little bit of a pain (especially since I need to pump my son's gun too, he's too skinny to get past 50 BAR).

I like the fact that you always get a good charge out of CO2 (until you run out of liquid), and I think you effectively get a lot more shots out of 20 lbs of CO2 than you do from an 80 cu ft air tank (but I don't really know).

If I got a good deal on a CO2 gun I'd definitely buy it. I'm kicking myself for not picking up a Feinwerkbau model 2 that was for sale locally a while back.

Steve.

[Rover]

Either one is a PIA.

Pick yourself up a FWB 65 or a good single stroke pneumatic such as one of the FWB 100 series or a Pardini K58 (still made).

Some say they are too feeble to cock them, but a bit of exercise is good for you. They really are not difficult if you develop an ergonomic technique. I'm nearly your age and find them easy to cock.

All you need is a gun and a tin of pellets and you're always ready to shoot.

[Guest]

Thanks Rover, you have a very good point there.

[paw080]

I'm sure this question has been beaten to death time and time again, and I apologize, but I am new to air guns. I am a pistol shooter, and would like to obtain an olympic quality air pistol. I see some used C02 guns on the market, and what I gather from all I've read that they are a thing of the past and compressed air is the thing now. But from what I see, a lot of the major records are still held by C02 guns. I don't need the latest up to date equipment as I am near 70 years old and could never hope to attain olympic status. Money is not an object, but I hate to waste it if I don't need to purchase the latest up to date equipment. Is there a major drawback to using CO2?? Any help would be greatly appreciated.

Hi RC, There is absolutely nothing wrong with CO2, unless as Steve Swartz
points out; you do not have a refrigerator. Yes, you will need a digital scale.
Unlike others who seem to be terrified of temperature effects on your
shooting,
I have shot matches and training with extremes in temperature with the
AP's constant ability to score tens. I've shot in 48 degrees and in 101 degrees.
Maybe my Steyr LP1 is more tolerant than other CO2 guns.
RC, I am almost 70 years old and vision, which is correctable, is my only handicap
when shooting with CO2. I find humour and value in Rover's
comment. I have several SSP's, one's an FWB model 100 and I've got one
recoiless spring gun, an RWS model 6M. there is something to be said about
the self contained convienience of those types. Be forewarned, you'll spend some
time training to build your muscles up to be able to shoot a 60 shot match.
So...go ahead and get that CO2 pistol, you shouldn't run out of propellant
during a match if you start with a full cylinder. I gave up counting shots that
my Steyr gave after 220...too boring...Please let us know what you decide
to buy; I'll respect and be delighted with your decision no matter what.
Have a great time with your new/used pistol.

Tony G

[Spencer]

A refrigerator is not essential with CO2.

CO2 is comparatively cheap, so a partial charge at room temperature can be vented and the cylinder will get much colder that a fridge or freezer (why gloves are a good idea).

The cylinder can then be filled - but weight it: this method can easily give an overfilled cylinder, with some interesting results.

Spencer

[rcmillerjr]

Many thanks to all who took the time to respond to my question. With the information I gleaned from this post I won't be near as shy about considering a CO2 system. Just depends on what pops (pardon the pun) up. R.C. MILLER, JR.

[cloudswimmer]

I've had a Drulov DU-10 in CO2 for two months.I had a Baikal IZH-46m for two weeks, sold it and bought a Steyr LP10 last week.All three have been fun so far, but i find the Drulov the easiest to fill by just dropping in a 12 gram cartridge.All three guns way out shoot me.I have a bad left shoulder from my body building days, and hand cocking the Baikal was starting to re-injure it.

Chris

[jipe]

Well, all what is said above is true and CO2 is surely as good as CA as technology. If you take the same pistol in CO2 and CA (exemple: an LP10 that was available in CO2 and CA), it will produce the same results.

But CO2 is probably dead now that the manufacturers have set a new rule for the duration of use of cylinders: it is maximum 10 years starting from the manufacturing date + a possible extension of 10 more years after an inspection for corrosion and a test by the manufacturer (i.e. sending the cylinder back somewhere in Germany) and as far as I know, there are no new CO2 cylinders manufactured since quite a long time now.

So, now already, the bulk of the CO2 pistols are in their "second=last" 10 years period = illegal since most of them was not re-tested. The last produced ones (it was around 1999/2000) will soon reach the end of the first 10 years period.

This means that, we like it or not, unless new cylinders are again maufactured, CO2 is almost dead.

Last point, if you look for a CO2 pistol, I think the only advisable ones (because there are still spare parts and decent support for them) are the FWB C20/C25 and Steyr LP1 or LP10 (if you can find one = very little sold or if you want to convert a CA one to CO2).

[Rover]

I don't see any "Date of Manufacture" stamped on my CO2 cylinders.

I guess you compressed air guys are SOL with the 10 year thing.

Actually, I would be very surprised to see any Match Director in the U.S.
care about this, although something might be said at a couple of the biggest matches.

How about it? Anyone looking over your cylinders?

CO2 can be bought almost anywhere, but you may have trouble finding CA in the boondocks. I've seen what happens when a scuba tank bursts, but never heard of it happening with CO2.[/u]

[Guest]

Jipe, inspecting the inside of my Pardini K60 CO2 cylinder is as easy as screwing out the valve with 2 drill bits and a multigrip and looking in the 25 mm wide end! Much easier than any air cylinder I have seen.
Interestingly there is an opinion in Australia that the cylinder does not need to comply with any Gov't regulations as the volume to pressure ratio is too small.

That is not the case for compliance with ISSF but since I don't shoot at international events I am not too worried.

[jipe]

Jipe, inspecting the inside of my Pardini K60 CO2 cylinder is as easy as screwing out the valve with 2 drill bits and a multigrip and looking in the 25 mm wide end! Much easier than any air cylinder I have seen.
Interestingly there is an opinion in Australia that the cylinder does not need to comply with any Gov't regulations as the volume to pressure ratio is too small.

That is not the case for compliance with ISSF but since I don't shoot at international events I am not too worried.

The Steyr cylinders are made the same => should be as easy.

The cost of inspection is not an issue anymore, FWB published official prices for both steel CO2 (40Euros) and air (60Euros) on their website. This is about 50% of the price of a new cylinder. It is not nothing but definitely cheaper than a new cylinder and also helps a lot for cylinders types that are not manufcatured anymore and cannot be bought new anymore.

The issue now is why this cannot be done for aluminium cylinders (CO2 and air aluminium cylinders cannot be re-tested and must be destroyed after 10 years) ?

[Mark Briggs]

Jipe stated, "If you take the same pistol in CO2 and CA (exemple: an LP10 that was available in CO2 and CA), it will produce the same results. "

While in general I'm sure this is true, I've lived just the opposite experience. My LP1 was originally Co2 powered. I purchased the necessary parts to convert it to CA and had Pilk do the conversion while at the World Cup at Ft. Benning. The conversion was quick, easy and professionally done - could't be happier with Pilk's work.

Unfortunately the same cannot be said for the performance of the CA conversion. I had previously done extensive testing with this pistol to find a pellet that performed well in it (and then purchased a case of the particular pellet that performed best). I could reproduce the factory test target with regularity when powered by Co2.

Following conversion to CA I once again performed pellet testing, with most disappointing results. Using the previously-selected "best" pellet, the CA-powered pistol produced groups significantly larger than with Co2. I experimented by adjusting velocity over virtually its entire range (even so slow that I could see the pellet fly and it would barely puncture the target). None of this brought any improvement. I have a stash of about 20 different tins of pellets that I use for testing and once again took these out and ran the pistol through multiple different brands, lot numbers, sizes, etc. Again, disappointingly-large groups were the result.

After growing frustrated with these results I switched the pistol back to Co2 power (it really is an easy change that only takes a few minutes). After spending about 15 minutes twiddling the velocity screw I was back to being able to reproduce the factory test target with my "select" pellets. Needless to say, this particular LP-1 is still configured for Co2, and shall remain that way as long as its feasible.

The moral of the story here is that airguns are very unique characters. While some may perform well with CA, some may perform better with Co2. My LP-1 is a clear case of a pistol which works best with Co2. As always, your mileage may vary! ;-)

One other point to add here... Having shot the same pistol with both CA and Co2 I have noted the recoil impulse with Co2 feels quite a bit less harsh than with CA, given the same pellet and same muzzle velocity. This being the case, Co2 makes my LP1 a more pleasant pistol to shoot.

[Oz]

One other point to add here... Having shot the same pistol with both CA and Co2 I have noted the recoil impulse with Co2 feels quite a bit less harsh than with CA, given the same pellet and same muzzle velocity. [...]

Since the CA and CO2 expand differently, I wonder if the pellet characteristic requirements changed for the pistol. With CA, maybe a different pellet would have responded better and would have ultimately achieved the factory group size. Maybe a slightly larger pellet fitting tighter in the barrel absorbs the stronger shock of the expanding CA differently and flies better. Just thinking out loud since the only thing that changed was the way/rate that the gas expands and pushes the pellet.

[jipe]

Using the previously-selected "best" pellet, the CA-powered pistol produced groups significantly larger than with Co2.

Very interresting. Can you give figures for the CO2 and CA grouping ?

Did you check the velocity: comparison of CO2 and CA velocities, velocity variation between shots with CO2 vs CA ?