hpa vs. CO2

[lil'feeby]

hey gang,
what is the performance difference between hpa and co2. what are the pros and cons of each? i want to go with a qb79 in .22 just don't know what type of air source to use for convenience, efficiency, velocity, and ability to be used in different temps. oh, can you guys tell me how i convert the 79  to hpa if that proves to be the best option. what is the optimum fps to be tuned for in one of these rifles. i know it's a bunch of questions, but you guys can handle them. thanks in advance.
peace rashid

[SDale]

CO2 will give you a higher shot count. HPA will yield higher MV, but lower shot count.

With CO2, charging is pretty simple. Either paintball tanks or AS bottles. HPA needs a pump or scuba set-up.

HPA runs the same in hot or cold weather, co2 is pretty much only good in 65+ degree temps.

HPA is more expensive initially, and CO2 will eat you up in the end.

Pretty much a "Pick your Poison" situation. I live in California with fairly stable temps, so CO2 is fine for me. I LOVE HPA, but there's no SCUBA shops near me and I absolutely HATE pumping!

[ribbonstone]

The HPA tanks that will fit on a QB79 will be either the 13 CI or the 22 CI tanks.   Are right, get a fewer shots from a full HPA bottle.  How much fewer?..depends on how fast you set the rifle to run.  Am using 4 HPA conversions, set to different power levels, in 4 calibers.  One .177 is set to give 11 foot pounds (using Kodiaks) and will get 85 good shots on a 13CI tank (850 psi output), running from 3000psi to 950psi.  A monster .25, pushing as fast as I can, will give about 40 shots (but 32 foot pounds per shot).  The other two (a 5mm and a .22) fall in the middle.

HPA doesn't really care how cold it is outside or how hot; can shoot just fine in freezing weather and won't lock up in 98 degree summers.

Can get HPA to shoot faster than co2, even when the HPA tank is regulated for mild co2 type pressures (850 PSI output).  Can get them to shoot quite fast if you use higher pressure output, but I'm not comfortable pushing a co2 system to pressures higher than 950-100psi (Yeah... know a lot of people do and get away with it... not me).

HPA costs.

#1.  You need a way to generate 3,000 psi air to fill the tank.  Even a cheap hand pump (and I wouldn't...would spend the $ for a Hill or an FX) costs a bit more than $200.  

#2. A regulated 13ci or 22 ci tank is going to cost somthing like $75-$85.

(Painball shop is not an option.  the HPA tanks will not just screw on and off becasue the nipple and gauge won't clear the barrel...and a paintball shop won't care for the idea of a rifle coming into the shop to get a fill.)

So we're up to $275-$285 for a tank and a way to fill it.  My local cost for 12gr. cartridges is $.40 each.  Lets use the lower estimate and call that 688 12gr. cartridges.  That's 344 loadings of the gun...or about 13,000 to 14,000 shots worth (if you only get 40shots per fill up).   think about that...28 empty 500 count tins (or 56 of the more common 250 count pellet tins).

Considering the cost of a QB79 as about $90...are into the HPA combo (gun...tank...pump) for about $370-$400.   Check out the prices for a Discovery gun/pump combo.

So why HPA?  

#1. If you've  a need for speed, can get the rifle shooting faster (but there ae some problems associated with that as well).
#2. Vel./power in cold weather doesn't fall off (and most hunting seasons are winter-based).
#3. You just like fiddling with airguns.

[lil'feeby]

thanks stone you really cleared things up for me. think i might save a little and get a disco combo makes a lot more sense than almost all the other options. i do like tinkering though. i live in south florida, the most humid place i have ever been besides the jungle, how will that effect the pump and what precautions should i take?

[howie1a]

If you get your air from a dive shot their is no moisture in scuba air it's the most dry air their is they filter it about 5 times and that is one of the cleanest air you can get, I am a diver and hold a master diver cert. I don't know a lot about PCP but I do know about clean dry scuba air. howie

[lil'feeby]

thanks a  bunch howie, i live in fort myers. there are several dive shops here so it should not be a problem. you guys have been a real help as always. thanks
peace

[ribbonstone]

http://www.compasseco.com/rifles-tech-force-c-1_34.html

[lil'feeby]

well now you went and done it! the chinese sure are excellent at cloning anything of value for the american consumer, and man they sure know how to make things hard to resist. i own a b28 in .22 already, it is a monster. i have killed more than a few squirrels at 50-55 yds and the pellet stopped just under the skin on the opposite side of the chest. i just may get one of these from comp. have you ever done business with them?

[ribbonstone]

Yes, have ordered from them before without a problem.  But be aware that their expected in-stock date is 10-1-09,  Reportedly a US made high pressure (3,000psi) tube.  

Expect folks that aren't use to fiddling around with Qb's might be dissapointed (might not), but the guys who are use to deburring, tuning, adjusting the trigger, etc. these might be a whole lot of fun.

Will find out once they start shipping.

[larspawn]

Wow, I didn't know they were making a Disco clone!  I wonder how good it will be?  By the way aren't the Disco's down to about $170 now for the Rifle alone?

[Boomer]

Sunshine Airguns has the Diso's for $155 and $269 with the pump in .177.