Challenger Arms Corporation Plainsman (CO₂) Pistol

[jackssmirkingrevenge]

My latest vintage acquisition taken apart:



The valve internals seem a little different from this example.

[DWTrull]

Nice box as well. Marked 22 on left side?
Where is the front sight?

[oldair]

Jimmie Dee's gun looks to be modified with a straight valve spring and extra piece to align it - yours looks typical.

Don R.

[jackssmirkingrevenge]

Nice box as well.

It also came with this literature:

Marked 22 on left side?

C 22 marking, is that significant?

Where is the front sight?

It seems to be the only part that is missing

Jimmie Dee's gun looks to be modified with a straight valve spring and extra piece to align it - yours looks typical.

Good to know, thanks

[DWTrull]

You have a second variant Plainsman. They are label C-22
Ther are 4 variants of the Challenger CO2 plainsman pistol

[jackssmirkingrevenge]

Thanks for the information, would you know the approximate date it was made?

[Pneumatic-Addict]

You have a second variant Plainsman. They are label C-22
Ther are 4 variants of the Challenger CO2 plainsman pistol

Dave,  Just curious which front sight would be correct for Jack's gun; the small single-band one or the figure-8-looking one?

[DWTrull]

single band

[jackssmirkingrevenge]

I made an extended endcap with a Ninja type fill nipple and replaced the two aluminum rings to seal the valve body with new ones machined from Delrin:



When I first tried it out the valve stem seal leaked and the material had obviously dried out and lost all flexibility, so I dug it out and replaced it with a Delrin ring and that did the trick.

I gave it a quick go at 1200 psi and boy is it loud:

[jackssmirkingrevenge]

Did some testing with 14.3 grain Crosman pellets and the power adjuster backed off slightly and starting at 1500 psi got the following velocities in feet per second:

404 - 401- 389 - 394 - 384 - 379 - 365 - 363 - 377 - 343

Pressure drop was around 500 psi.

Firing in slow motion:
 




Powder adjuster details, the central part is what strikes the valve stem and unscrewing it reduces

[jackssmirkingrevenge]

Added a muzzle section with front sight and shot a standing ten shot group from four meters, starting at 1800 psi.  It's clearly no tack-driver but all shots fell within a 60mm circle so it's more than usable for a bit of plinking

[xcalibur]

Added a muzzle section with front sight and shot a standing ten shot group from four meters, starting at 1800 psi.  It's clearly no tack-driver but all shots fell within a 60mm circle so it's more than usable for a bit of plinking

As cool as it looks, this just seems like a bad idea to do on a pot metal plainsman.

[Pneumatic-Addict]

Challenger Arms Buntline Plainsman

[jackssmirkingrevenge]

Challenger Arms Buntline Plainsman

It is a bit

As cool as it looks, this just seems like a bad idea to do on a pot metal plainsman.

A fair concern however when you look at the chamber, the frame is not exposed to pressure.  It's all contained within the valve body and the steel cartridge tube.  What is critical is the threads at each end of the frame that are holding things together, but there is considerable engagement on both sides, I don't think 1800 psi is pushing it too far.

I tried another 10 shot group at 5 meters at rest and it was much tighter, the first shot is the highest but then apart from one flyer it wasn't bad at all considering. 

[xcalibur]

As cool as it looks, this just seems like a bad idea to do on a pot metal plainsman.

A fair concern however when you look at the chamber, the frame is not exposed to pressure.  It's all contained within the valve body and the steel cartridge tube.  What is critical is the threads at each end of the frame that are holding things together, but there is considerable engagement on both sides, I don't think 1800 psi is pushing it too far.

I tried another 10 shot group at 5 meters at rest and it was much tighter, the first shot is the highest but then apart from one flyer it wasn't bad at all considering. 




[/quote]

I don't disagree; the receiver threads are the critical points in that setup. You have to keep in mind, though, that the receiver is also a 70+ year old zinc alloy casting that may or may not have flaws or zinc rot. As you probably noticed, there's no steel threaded insert inside. The casting itself is threaded to accept the tube and valve nut. There are only five full threads on the valve nut, so it seems plausible to me that 1800PSI, pushing rearward on the valve, might cause those few threads to fail at some point.

The receiver threads may not have yielded during test firing and there's a chance they won't even at 2000PSI, but what happens when the next owner thinks a 3000PSI fill is a good idea because that's what he puts in his Benjamin Marauder. I suppose best case scenario would be that the air pressure just blows off and only a collectable airgun is ruined. Worst case; it blows the valve, striker and rear plug out the back ruining somebody's day.

I like the modification you've done on it, but bulk fill CO2 might be a safer choice long term. That, or figure out a way to stake the valve in place so that the valve nut is just a secondary safeguard.

[jackssmirkingrevenge]

You have to keep in mind, though, that the receiver is also a 70+ year old zinc alloy casting that may or may not have flaws or zinc rot. As you probably noticed, there's no steel threaded insert inside. The casting itself is threaded to accept the tube and valve nut. There are only five full threads on the valve nut, so it seems plausible to me that 1800PSI, pushing rearward on the valve, might cause those few threads to fail at some point.

Wise words indeed, and after having "proofed" it I don't see myself using it beyond 1500 psi, which is approximately "left in a car on a sunny Summer's day" CO2 pressure equivalent.  You're also right that it might one day be passed to someone else without the requisite warnings so some sort of marking is in order.

[DWTrull]

Can you verify if the barrel and gas tube are steel or bronze with a magnet.
They both appear to be steel.

[jackssmirkingrevenge]

I'm almost certain they are steel but will confirm later today.

[jackssmirkingrevenge]

Testing with a magnet I can confirm that both barrel and chamber tube are steel.