Today reader Ian McKee, whose blog handle is 45Bravo, looks at bulk-fill CO2 guns.
If you’d like to write a guest post for this blog, please email me at blogger@pyramydair.com.
Take it away, Ian
A revisit to bulk fill airguns
by Ian McKee
2006 bulk-fill report Part 1
2006 bulk-fill report Part 2
This report covers:
- Bulk-fill airguns
- Not all bulk-fill tanks are the same
- Please learn from my mistakes
- Vintage Crosman tanks
- How to do it
- Chill out
- Fill caps
- Pellgunoil
Many of us have vintage airguns. Many are springers, some are multi-pumps and some are probably CO2 — powered by either 12-gram cartridges or the older smaller 8-gram CO2 cartridges that were also known as “seltzer chargers”.
Bulk-fill airguns
But back in time you will also find bulk-filled Crosman guns that came with a reusable CO2 bottle that was charged with 10 ounces of liquid CO2. It is shown below. When it was time to refill your airgun that bottle was attached and filled it with a charge of gas.
The idea back then was when your 10-ounce tank was empty, you mailed it back to Crosman and they sent you a full tank for a nominal fee. That sounds like modern days where you have to pay a monthly service fee for just about everything. One day an enterprising individual figured you could fill your Crosman tank at home from a larger CO2 tank and never have to be without the use of your airgun while waiting on the return tank.
[Editor: It also sounds like what Giffard did in the 1870s — mail in the airgun’s tank for refilling by the manufacturer.]
You can buy 20- or 40-pound (the weight of the liquid CO2 the tank holds) or larger tanks to fill your CO2 paintball and airguns. You just need a fitting that allows one tank to be attached to the other.
Not all bulk-fill tanks are the same
My first foray into bulk-fill CO2 was in the mid 80’s with paintball. I bought a large 125-cubic-foot CO2 tank (bigger is always better when you are young) and bodged together an adapter to fill the 12 oz. tank of my paintball guns.
I quickly discovered my lack of knowledge about the hardware as I had to invert the tank to get the liquid CO2 out of the large tank and into my bottle that fit on the gun.
But the large tank I had bought — while it was a CO2 tank, was designed to dispense CO2 GAS, not liquid. In order to get the liquid out, I had to build a frame from wood that would hold the 4ft tall, 70 lb (the actual weight of the EMPTY steel cylinder) CO2 tank upside down before I could fill my small paintball tanks. When the tank was full of liquid CO2, it was considerably heavier.
Please learn from my mistakes
Just know if you decide to go bulk fill, look for a tank that has the words SIPHON TUBE stamped on the neck. Those have a tube that runs from the valve to the bottom of the tank as it sits normally on the floor. When you open the valve on the large tank, the pressure of the CO2 gas at the top of the tank presses on the liquid CO2, forcing it up the siphon tube and into the smaller bottle you are filling.
This CO2 tank has a siphon tube and doesn’t need to be inverted to dispense liquid CO2. I wish I had known then what I know now. Those two little words would have saved me a lot of headaches. But those were PRE-Internet days.
Vintage Crosman tanks
The Crosman tanks that come with the guns have their filled weight stamped on the valve knob from the factory. That served two purposes. You could weigh the tank and know how much CO2 you had left. And if you filled it yourself, you could be sure not to overfill it.
The 10-ounce Crosman bulk-fill tank. The Mark 1 pistol is not bulk-filled. It’s shown for scale.
35.5 oz. is what it should weigh when full BUT CHECK IT ON YOUR SCALE FIRST.
How to do it
To fill the 10-ounce tank, attach it to the larger tank and open the smaller tank valve. Then open the valve of the larger tank and the liquid CO2 will rush into the smaller tank because of the pressure difference.
You can hear the liquid transferring plus the tank being filled will get cold on the outside. You will hear when it stops. You then close both valves and then unscrew the small tank. Be aware that there will be a small jet of CO2 that is released from a vent in the fill adapter.
Chill out
If you first chill the smaller tank before filling it you will get more liquid into tit. In the paintball games we would put the small tanks in an ice chest with our drinks for a few minutes to get them cold before filling.
Now that you have the bulk tank full of liquid CO2, it’s time to fill the gun. We will use a Crosman 600 that has been modified to use bulk fill. (Spoiler alert — you will see a blog with a full test of this gun soon.)
Fill caps
Some guns have the bulk fill port covered with a small brass cap, or some other type of cover to keep dirt and debris out of the system. Some may not have a cover.
Remove this cap from the airgun first, and try not to lose it.
After the fill port cap is removed, thread the Crosman tank into the fill port. Once that is done, invert the tank so it is vertical above the gun being filled. If the gun is completely empty, make sure it’s unloaded. Then cock the gun to remove hammer pressure on the valve stem and put the gun on safe. Then open the fill valve (the round knob on the 10-ounce tank) slowly, and the gun fills with liquid CO2. You will hear when the pressures equalize and the liquid stops flowing. Chilling the gun before a fill also helps.
With the 10-ounce tank on top and the airgun underneath, open the tank valve.
When you hear the transfer stop, close the valve on the bulk tank. Then unscrew the tank from the airgun. When you unscrew the tank, again there will be a small jet of escaping CO2 that was in the small area between the tank and the gun.
Dry fire the gun once or twice just to check the functioning. Load the gun and have FUN!
Pellgunoil
With modern CO2 guns we have gotten used to adding some Crosman Pellgunoil or some automatic transmission fluid stop leak for each new 12-gram cartridge. It’s to seal the gun and to lubricate the action. When bulk filling you can add a drop or two to the fill port before attaching the bulk tank.
Then when you open the valve to fill the gun it blows the lubricant through the system to lubricate the gun and keep the seals in top shape.
That’s about it.
This blog was just to get new readers an overview of the bulk fill process.
BB will review soon a beautiful Crosman 600 that has been upgraded in several ways.
Back in 2006 BB wrote two blogs that covered the bulk-fill process in far more detail than this one. As many readers may not have either been reading the blog since 2006, or may not have read through the many early blogs, they are linked at the top of this blog. They are very informative and may encourage some of you to explore the vintage bulk fill airguns. Or it may encourage some to dig through the closet and dust off an old bulk fill airgun and exercise it a little.
If you happen to have a Crosman 600 semi auto pistol that needs a reseal, there will be an upcoming blog about how to do that. So dust the old girl off and get it ready,
Shoot safe, and have FUN!
Ian
Ian,
The way you described the recharging of the small CO2 tanks still hold true over here. Except the reseller uses the big tanks (same size as for acetylene) lying at an angle downwards (no siphon tanks over here on the Philippines to my knowledge). All our locally manufactured CO2 rifles are bulk filled. Nobody here makes CO2 cartridge air guns.
Siraniko
I didn’t know that, thank you for sharing that information.
I have seen many photos of some pretty unique Airguns out of the Philippines.
I wish we could get some of them imported here. (The grass is greener over the fence syndrome.)
Ian.
Ian,
Thank you for an excellent report. You obviously enjoy your subject matter and did a great job of covering it for us.
An unintended consequence may be that you have made many of us want a new historical airgun blog about the accuracy of BB’s Giffard carbonic rifle. (How about it, BB?)
Have a great weekend.
Bill
Bill,
I no longer own the Giffard. Someone else does and he is a reader of this blog. You will read about it on Monday.
BB
bill,
You will be able to read a bit more about BB’s Giffard, hopefully in the very near future. 😉
RidgeRunner
Could it be that RR has finally landed that eye candy from the l870’s?
Deck
😉 I am thinking I need to back away and concentrate on some of these “old gals” just a bit more. This “new” stuff is better handled by others.
Thanks, Ian! I have several, vintage Crosman CO² guns, including a couple of 600s, one of which may become Bill’s in Greece if we can work out the details. So I’m looking forward to more on resealing the 600. I found a fellow who makes an adapter to use 12 gram CO² cartridges to partially fill bulk-fill guns. I have a case of 500 carts for the Mark I and IIs that you taught me to reseal.
Does anyone know if due to Crosman’s “restructuring,” whether parts for these vintage guns will become more scarce?
RG,
I get my parts for these “old gals” around here mostly from “scavengers” who disassemble non-functioning airguns for parts. Some of the parts I use are new and remade by some. If you “collect” some of these “old gals” like I do and want them to function as they used to, you soon learn whom to contact for what.
BB also knows of many of these folks. Many of them are in Europe. The wonders of the internet are a big help.
Ian,
Thanks for this blog. I just happen to have an “old gal” hanging around here that is set up for bulk filled CO2. I have not had a chance to get to her as of yet, but I hope to do such soon.
It certainly is nice to know of someone else who has a clue what to do with bulk CO2. I know there are many out there who do know about using this gas. Finding them is another issue. Unfortunately, paint ball has been slowly going away. It is being replaced with those plastic bbs and now those gel thingys.
Will paint ball make a comeback? Who knows.
P.S. It is most helpful to someone such as myself to know of those two little words stamped on those big bulk tanks.
RR, paintball is still alive and well. Several of my coworkers are into it.
They have a very dedicated following.
In recent years paintball has been switching to HPA(High Pressure Air) like our PCP’s.
They use 4500 psi carbon fiber bottles, but they are regulated down to CO2 pressures.
The benefits are: they get a very high shot count per fill, the HPA doesn’t have the pronounced cool down that CO2 does
Being many paintball guns are now electronically operated they can be reliably full auto or burst mode.
The older guns can be used with the regulated hpa bottles so the 2 fingered fast firing mechanically operated guns are still able to hold their own on the field.
But yes for the backyard budget blaster (BBB?) it has been replaced with airsoft.
Ian
I played paintball once years ago. I did get hit a few times. Ouch! Thankfully, it was not with a full auto. That would have been OUCH! OUCH! OUCH! OUCH! OUCH! OUCH! OUCH!
Not fun in my book.
Ian,
It has been on a long, slow death march out here on the right coast. The good news is that a friend of mine goes to a major war game every year where they use the updated paint ball guns. He has one capable of full auto. He says there are some superb sniper rifles out there also.
I briefly considered joining up with him, but Mrs. RR would very likely either kill me or divorce me. She will say I have enough hobbies now.
Still technically airguns, just different projectiles, so same hobby. ;o)
Like Obi-Wan says, it just depends on your point of view.
RG,
I do not think that would work with her. She has not been happy when I have brought “new” airguns in here. Period.
Great info next time I exchange my tank I’ll make sure I get one marked SIPHON TUBE!
Thanks for the tip Speakski
Always glad to help!
Ian
45Bravo,
After shooting multi-pumps and single stroke pumps as a kid when i returned to airguns as an adult it was the pumpers with the addition of CO2 powered 22XX pistols and carbines. I soon got introduced to Bulk Fill CO2 and Quackenbush Steel Breeches and threaded free-floated barrels in .25 caliber. Buying a 20# Siphon Tube cylinder was a no-brainer. I also bought two 10M PCP for Olympic Style Target shooting.
There is a field expedient method for getting full gun fills by chilling the gun’s CO2 reservoir by venting a small blast of CO2 and then doing the complete fill.
I bought an AIRROW MODEL A-8SRB STEALTH that could be charged with air, Nitrogen, or CO2. That was my introduction to the Big Bore Dark Side. The Swivel Machine CO. rifle used Paint ball Catalina CO2 cylinders or Catalina 3,000PSI rated Hpa bottles. CO2 gave a much higher shot count then even the 22 cu.in. Hpa cylinders. It feels like it was all from the Stone Age but the Lothar-Walther barrels were just as good back then.
Thank you Ian for the flood of memories your Blog on CO2 Bulk-Fill brought with it!
shootski
Ian, this is a most interesting treatise; thank you. 🙂
Ian
Your broad knowledge of air and gas guns and willingness to share it is much appreciated. Plus hanging out with BB on trips such as this doesn’t hurt.
Thanks
Deck
Interesting, also on CO2,
https://hardairmagazine.com/reviews/does-the-umarex-komplete-shoot-co2-surprise/
I would not have thought it would work but looks like it does.
Mike
Mike
I hope this isn’t too good to be true or an early April’s Fool. One would think Umarex ads for the Komplete would tout the dual fuel capability. Wondering about long term availability of nitrogen cartridges was a concern for me if this gun didn’t sell well.
Deck
Decksniper,
Not to worry Deck even Walmart has you covered: https://www.walmart.com/ip/18-gram-Nitrogen-Gas-Cartridge/405951145?wmlspartner=wlpa&selectedSellerId=101042393
Nitrogen gas is supposed to be cheaper by the pound than CO2 ?
2 X 32 grams at PAir: https://www.pyramydair.com/product/umarex-nitroair-n2-cartridge-2-pack?a=16820
Seems to be way cheaper.
Tractor Supply Co. sells them as well as a bunch of other shops.
shootski
Deck,
I just think that it is important not to use pellgunoil if you use the 88 or 90 gram co2 because if you go back to the high pressure nitrogen there might be a problem, think bang. Best to use silicon oil instead.
Mike
Mike in Atl,
Actually Nitrogen will not support combustion that is why it is used in aircraft tires.
The place folks get in trouble with explosive combustion is with Oxygen (O2) at almost any pressure and breathing air at high pressures like what is found used in PCPs.
shootski
Mike in Atl & Shootski
Thanks to both for responses. The Komplete rifle has my eye on it. New or unusual designs are fun for me. My Izzy 61 design isn’t new but it sure is different from anything else I shoot.
Deck