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LANNY HAFF · New Member

I was wondering if it would be possible to modify a 2100 for CO2? If so what would be needed as far as parts go? I like the 2100 but pumping gets old fast. I have a bulk fill QB79 which is a nice gun but it is heavy. I was thinking along the lines of using a 9Oz tank or a 24Oz tank + maybe using a bulk fill set up for a QB78. Any ideas? Lanny

lampy · Veteran Member

I was thinking about the same mod a couple days ago. I'm in the middle of another build right now so I haven't given it much thought yet. I'm leaning more towards using 12 gram cartridges.

LANNY HAFF · New Member

I was thinking along those lines, I wanted to bulk fill to avoid the weight of a large co2 tank. The small co2 cartridges would work also. Would you know if the original 2100 valve would work? What I mean is if you had a different main tube like 1 from a 2240 or a co2 tube that would fit with out to much hassel, would the stock valve charge + discharge like it's suppoed to do or would you need some other type of valve? Let me know your thoughts on this + maybe I can come up with some ideas that would help us both. Thanks Lampy Lanny

lampy · Veteran Member

I think the 2100 valve would work with CO2 I'm not sure if the check valve would cause problems, if it did it could be disabled/ bypassed easily enough.
There are a few problems that come to mind right away. How would the cartridge be pierced? The O.D. of a tube from a 2240 or a 1077 is a larger diameter than the pump tube of the 2100. If a 2240 or 1077 tube could be made to fit the 2100 receiver how is the gas going to get from the tube to the barrel?
Bulk fill would be the way to go, then you could keep the O.D. of the tube the same as the stock 2100 tube. Then the stock valve could be used and no worries about getting the CO2 from the valve to the barrel. A custom tube would have to be made with a fill fitting of some type.
I might be mistaken but I think Tom Gaylord did a Blog about turning a 2100 into a PCP, I'll have to look into that. That could be what got me thinking about this mod.

AirGunEric · Site Admin

It's not terribly practical based on the effort that would be required;

-bulk fill only due to tube size and lack of piercing pin
-tube is slotted for pump arm, meaning shortening it to below slot and then putting on a sealed top to hold the QD connector for filling
-eliminating the check valve (perhaps drilling out it's center would work)
-figuring out how to re-attach pump arm (for use as a forearm) as it would not be held in place by the no-longer-existing pump linkage

strikes me as simpler to get a 2240, add a longer barrel and install a stock (i.e. make a 2260, sort-of).

lampy · Veteran Member

LANNY HAFF · New Member

1 reason for doing a100 is I already have 1 plus I'm retired + 74 yrs. young so I have plenty of time on my hands to modify or possibly break stuff. Most of the time I can figure things out fairly + if I have a problem I can always ask. P.S. I'm on a fixed income so money is something of an issue. But you did bring up some good points but I'll let you guys know what happens. I'm a pack rat so I have lots of raw materials. Lanny

lampy · Veteran Member

Lanny
Looking forward to hearing about your project. Have fun!
Temps are supposed to climb up to freezing this weekend so I'm hoping to get some work done on my project during this heatwave.

Big Bore Bart · Member

Unless you are capable of making an entire tube (or shortening the original),,,It ain't gonna work. The 2100 tube is 3/4 OD, a 22xx CO2 tube is 7/8 OD and will not fit the receiver. A CO2 cart is ~.735 OD. I have successfully made PCP tubes for a 2100 and a 2200 from scratch, however I do own a lathe. A bulk tube would have to be made the same way. I did make an adapter to connect a remote tank to the back half of a pumper valve.

LANNY HAFF · New Member

I've researching this project + I figured out how to bulk fill the gun but I have some concerns, on pumpers every time you pump it it increases the psi in the valve not the tube. The wall thickness of the valve is much thicker than the main tube. Now when co2 gets hot the psi rises from 900psi at 75 degrees to over 1200psi at 120 degrees which in FL where I live is not hard to attain. The main tube is thin wall tubing which I don't know how much psi it could stand without exploding! Do any of you people have any thoughts on how many psi the main tube could sustain? I just want to mod my gun not injure my self.

Big Bore Bart · Member

Using the yield strength of 1018 steel =53,700 psi, you get a 3:1 safety factor at 3100 psi. The major factor will be securing the valve and end/fill plug.

lampy · Veteran Member

I'm giving this project more thought, I should have a suitable donor in a Crosman 766 in a couple weeks. My idea is to use 3/4" DOM tubing to replace the pump tube. Use the stock exhaust valve. A Disco fitting for filling. Should be a simple conversion. Of course I'll have to try it on HPA also. Now to get parts on there way.

Big Bore Bart · Member

Is very doable. Cool

I have made two HPA tubes for the 2x00 series, one for a 2100, and one for a 2200 (still working on tuning the 2200). Forget the DOM and use seamless 4130. When you get the tubing, get the MTR for it, you will be surprised at the true tensile and yield nos. The tubing I used has a yield of 115800psi. The factory spring and striker works with a 4300psi fill in this gun. The Disco is a 7/8" tube, so the fill fitting would need to be turned down.

I just made my own integrated end plug and fill fitting.

Five 6-32 full height socket cap screws in shear hold it and the valve in place. The screws set down in the plug and valve so they are flush with the tube. The C-Bore is .221" which is the dia of the heads.

It currently does ~22fpe. (Those are 9.8gr Winnies.)

DavidSaunders · Veteran Member

lampy · Veteran Member