HPA 12g...
 

I was on a flight from ATL to DTW and was thinking about paintball to keep my mind off of all the hundreds of systems that could fail on the 757-200 I was trapped in, and I had a thought. How big of a HPA tank would I need to replace a 12g? I dunno WHY, it just entered into my mind.

As far as I have been able to figure, a 12g CO2 capsule is about the same as a 1.21/4500 or 1.82/3000 HPA tank. I did the math because it was kinda fun (and may be wrong...). But then I started thinking - "So what? Why would you want such a thing?"

Well - it would be handy for testing the relative efficiency of various markers. Even those who dislike co2 or testing can take place on non-standard days. It would serve as a nice efficiency benchmark that is a bit more "same" than 12g's which tend to vary from unit to unit.

Also, if someone makes them, there will be those who want them.

It would be a re-fillable 12g - so the first one could be expensive, but could pay for itself after a few years of play.

I figure the internal volume would be about an inch, and the internal length would be about 2" for a 4500 psi "tanklet". They would all include the standard HPA regulator/ASA adapter.

Sadly, it won't fit a PGP or Desert Duck or any other gun that holds the 12g in the grip...

Anyway - just a weird though.

What happens when you need to change a 12g? Would you have to unsrew it from the asa and screw in a new one?

would you carry multiples of these around?


I don't see the practicality of it.

The co2 cartridge is not meant to hold hpa pressure.

re-fillable 12ies have been done in the past and there been a thread on here before about it. It is very unsafe because of the thread on the entrance will have thin walls.

12g co2 cartridges can get 50 or more GOOD shots on the right gun (meaning the pressure remains at over 600 PSI)... to do that with HPA requires a considerably larger volume. the smallest HPA tanks we have (8CI) are supposed to get around 100 shots at best... effectively the same energy as two 12 grams, and it's a much larger volume at much higher expense: an 8CI tank with a low-cost regulator costs the same as about 250 12 gram cartridges.

Inversely: a good hundred dollar investment in 12 grams will get you 10,000 shots with a high end, efficient stock class gun (which is 40 times 250 shots, so at least a year of regular, dedicated SC play, or several years for more casual shooters).

Practicality? - I don't see it either. But it would be cool, and there is at least one freak out there who would LOVE it :)

Maybe hinting at something almost resembling practicality - these little tanks would be easy to fill with one of these -> [LINK]

We're not talking about refilling an expended 12g with HPA, we're talking about making a refillable HPA replacement for the 12g. Imagine a regulator from a HPA tank, attacked to a 1.25" OD bottle stuck to it.

Okay - so my math seems to have been off - I guess it would be a 4CI tank - however an 8CI tank would be very nice for testing relative efficiency of various guns.

I don't know if the $100 benchmark is the way to go... a 13/3000 tank is about $50, equating to 5,000 shots with an excellent gun for the same price. That $50 tank should result in about 150(+/-) in an excellent gun per refill. And I think (and may well be wrong) that the 13/3000 8/3000 and 4/3000 would be exempt from hydro. At any rate, most of the cost of the virtual 12g would be the reg.

The reason a 12 gram is a viable power source is because of the liquid co2 in it. The energy density is off the charts compared to HPA because of the phase change from liquid to gas.

I have my doubts that you could get enough energy packed into a 12 gram-sized container just through compression, at least not enough to be useful. The walls would have to be thicker, you'd need a regulator downstream, and you'd have to over-engineer the neck so that there's no chance of it being disengaged prematurely.

By my standards, a loose 12 gram is just barely on the good side of the fun/scary line at 800-1200 psi. A 4500psi 12 gram sized tank that doesn't need any phase change time to tap into its full potential energy would put a nice hole in a skull.

fixed for ya :p

Hmmmm... perhaps I have mis-labelled this.
The idea is not to cram a lot of HPA into something the size of a 12g. The idea is to build a very small HPA tank that contains roughly the same amount of energy as a co2 12 gram.

An 8/3000 is about the size of a soda can, so a 4/3000 would be about the same length, but would have a smaller OD. It's something that would have an ASA and pin valve, just like a 8/3000, 68/3000, 90/4500 or any other HPA tank.

As for the hazard to an Elephant... If something the size of a 12g filled with 4CI of 4500 psi nitrogen was really as dangerous as you stated, we would use them to hunt deer and wild bore, and leave the 3 1/2" magnum 12ga slug rounds at home - same kill, less noise. I could hunt in town ;)

It's kinda funny - back in 1992 I was at a field and said "Y'know, we should drop this stupid co2, and start using nitrogen to power our guns. It's much more stable and is not effected by temperature change." the response - "Are you nuts! Whose gonna play paintball with a 3000 psi tank on their gun?" (of course people were already using it, but at this field in rural MI, no one had ever heard of such a thing). Around 1994 I looked over at my buddy and said "What I should do is use a micro-switch and a solenoid instead of that mechanical seer." the reply - "That's stupid! How much faster do you need to shoot?" (At the time I was using a Stingray...). Recently, I wanted to build a gun - a spool valve fully-mechanical gun using a pneumatic valve/switch for the trigger... I think GOG (and Yoda) beat me to it. Maybe I'm WAY off on this... But maybe there is some whacko thinking "that would make my old pump more accurate because of increased consistency regardless of ambient temp, AND I could refill it myself.... Hmmmm...."

I doubt I'm gonna see the day when guys are using 4/3000 or 2/4500 tanks, but it would be hellaciously cool to put one on the back of my old Nelson(s)

Of course you have had the idea and were responsible for thinking up the first air tank, electro pneumatic gun, and pneumatic spool. You know I also thought of eBay. But you didn't build anything nor take it past the idea so why will this be any different. You spit an idea someone says no and you dont go any further. Why even ask?

Leland (known for high end CO2 12grams) makes 4.4ci 3000psi disposable N2 and HPA carts. These are obviously unregulated, though 3000psi is at the upper limit for co2 burst discs.

I see them all the time at homebrew stores, though the ones you usually see are the 1700psi ones (designed to be used on co2-powered taps). You also see N2O 12grams in stores, used for whipcream dispensers. They are often called "Nitrogen Carts" but is stored as a liquid, and has the same basic properties as co2. (similar pressure, problems, except its also very corrosize).

Leland also makes bigger disposable nitrogen/HPA carts, but then you won't be able to use existing 12gram changers.

They all seems like a lot of work, when the end result will either be a common 13ci tank, or stick with co2 12grams