Fill a Discovery from 12g CO2 cartrdges?

[robtmc]

Did some searching and came up empty.  Crosman hypes the dual fuel thing but only talks about an adapter that fits the bigger CO2 tanks, not Powerlet sizes.

I have a SCUBA tank for 2,000 psi fills, but it would be nice to take advantage of the tons of CO2 cartridges on hand for my pistols.  Would avoid trekking into the garage as well.  Would rather not invest in a $$ small air tank if a way to feed the rifle from the 12g was available.

Has anyone made an adapter to fill the Disco from the 12g cartridges?  I am sure it would be low power, but very convenient while plinking/target shooting from the porch.

If there is a major flaw with doing this, fill me in.

[nomobux]

   Somehow, I just don't see that being too feasible.

[Ribbonstone]

Don’t think it’s going to work.

If we had a paintball tank with 8 oz, in it and we wanted to put 2 ounces in the gun, no problem. Even if the paintball tank only held 4 ounces, would still get to even when they both held 2 ounces.  But if the tank only held 1 ounce, I’d expect them to even out at ½ ounce each.

By that logic, a 12gr. should end up with 6grams in it and 6 grams in the gun, BUT THAT IS WRONG because the above assumes at least equal internal volume between the gun and the fill tank.

12gr. too small a volume.  Inside volume is  small. Lets say 22cc’s for this discussion.  Discovery tube is 135, or about 6X as large.

So when you hook up your first 12gr., would even out with something like 10grams in the gun and 2 grams in the 12gr..  Hook up another 12gr. and it might even out at 11grams in each.

You could drive in more co2 by cooling the gun and heating the fill tank.


Then I got to playing.  IF I had a manifold that could hold and pierce 20 12gr. and not have any of them leak., then I’d be back to 8 ounces of co2 on one side and an empty gun on the other.

Do think that with enough custom work, could produce a piercing Disco valve and a piercing end cap (long enough internally to take up the excess space) and run one like a QB.  But the cost of making those two things would easily buy several QB’s.

[gnef]

The only thing I can think of that could work would be if you could use a device to tether the 12g cartridge and keep it connected to the foster fitting securely until the 12g cartridge was empty.

I could see something that is used in homebrewing: http://morebeer.com/products/co2-injector-w1-cartridge.html

If that were modified to have a female foster connected to the 1/4'' female flare fitting, it could work.

Do I think it is worth that effort though? Not at all.

[robtmc]

What got me to thinking was the Hammerli 850 is supposed to have an adapter that used two 12g cartridges.

The whole CO2 operation is new to me, and just recently read about the phenomenon of the liquid CO2 boiling off to provide a constant ~900 psi.  Sounds like even if you could charge the Disco reservoir, a 900psi fill is not going to last very long.

Dunno how the dual fuel Crosman thing is supposed to be very effective unless tethered to a tank.  Yeccchhhh.

[shultz]

I think this would work... never tried it though.
one of these:
http://www.ebay.com/itm/QUICK-CHANGE-12-GRAM-12G-CO2-ADAPTER-DUST-BLACK/271252668149?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D27%26meid%3D666880037419590026%26pid%3D100033%26prg%3D1011%26rk%3D4%26rkt%3D4%26sd%3D310343197499%26
screwed into one of these:
http://www.ebay.com/itm/Rebel-Paintball-Gun-Universal-2-hole-Bottomline-CO2-Tank-Adapter-ASA-duckbill-/190867936917?pt=LH_DefaultDomain_0&hash=item2c709d9695

Topped off with one of these, link is for EXAMPLE ONLY! get a foster of better quality:
http://www.ebay.com/itm/Paintball-CO2-HPA-Compressed-Air-Fill-Adapter-Female-Quick-Disconnect-1-8-NPT-/390644558682?pt=LH_DefaultDomain_2&hash=item5af43aeb5a

Once screwed together, connect to the Disco fill nipple, install CO2 cart, pierce and shoot.... at least that's how it works on paper so to speak...

[Ribbonstone]

Misunderstand the "boil off".  You are filling with liquid co2 (which is why co2 is always sold by weight...grams, ounces, pounds).  The liquid co2 you bulk fill into the gun "boils off" are creates gas co2.  So as you shoot, more liquid boils off and replaces the gas you used in the shot, so the pressure stays constant for as long as there is any liquid co2 in the system and as long as the temperature stays about the same.

Co2 is very temperature sensitive, gaining pressure QUICKLY with temperature rise.  So you 900psi at room temp can well become 1100psi on a warm day (and even more on a hot day).  So in winter, co2 might produce only 500-600psi, but in summer might produce 1200psi.

EDIT:
The above solution would work, at least for a few shots, and I'd leave the 12gr. attached.  Not real sure how many shots 12gr. of co2 spread out within 152cc's or volume would give (135 for the gun's tube and about 22 for the 12gr.)  If 12gr. just becomes gas, not having enough volume to leave behind some of the replentishing liquid co2, then it would act like any other gas and decrease pressure with each shot.  Guess I could empty the Discovery and put in 4/10ths of an ounce of co2 and find out.

[robtmc]

Leaving some contraption attached sort of defeats the idea so that is a no-go.

After some reflection on the source of gas pressure from CO2, it looks like the only way to do a fill and remove the cartridge would be if the liquid could be mostly transferred.  How well that would work and if it is a good idea to have it in the reservoir, I dunno.

Think I will drop the idea as an idle curiosity of an idle mind.