The Challenger Arms Corporation Plainsman (CO₂) Pistol (1954-1958)

In a previous article, I wrote about the Challenger Arms Corporation Plainsman “pneumatic” air pistol. That article described how the pneumatic Plainsman was effectively a further development of the Apache air pistol. Both pistols were designed by Albert Dale Fogel who was a financial partner and Vice President of Design and Production at the National Cart and Challenger Arms Corporations. [1]

In the mid-1950s, the National Cart Corporation was in financial difficulty which inevitably resulted in the downfall of both companies. The Goodenow Manufacturing Corporation of Erie, Pennsylvania revived the Plainsman line of airguns in 1954 and added the CO₂ gas variant to the pistol, rifle and air shotgun lines. However, production lasted for only four years and ceased in 1958. It’s interesting that Goodenow was able to continue using the Challenger Arms Corporation name on the air guns that they manufactured. Whether they bought the Challenger Arms Corporation brand or obtained the rights to use the name is still a mystery. [1]

The Challenger Arms Corporation Plainsman CO₂ air pistol was introduced to Jimmie Dee’s air gun collection about six weeks ago [this article was originally published on August 11th 2016 – Ed]. It was purchased from an online auction with only its cosmetic condition known. On delivery, the true condition of the pistol was revealed. The box was in a very poor state with one side of the lid missing. Nonetheless, the pistol has its box and I am confident that I can make a replica to provide the pistol with some improved protection. Interestingly, this box has a linen effect print whereas many others that I have seen have a wood effect print. [2]

Whilst it looked in good condition from the auction photographs, the pistol has been repainted with a brush. However, it functioned perfectly and all parts were present and undamaged. I considered that as it had been poorly repainted, I would endeavour to restore the pistol properly.

The first step was of course to disassemble it into its component parts. The black “tenite” grips are attached with a single screw on each side. A grub screw holds the blacked brass barrel in place whilst the foresight is a push fit over the barrel’s muzzle. The bolt probe was removed by tapping out the locking pin and then withdrawing the bolt from the rear of the pistol. The hammer and cocking knob was removed by unscrewing the rear cap and withdrawing with the trigger pulled. The trigger is held in place with a roll pin. The valve unit is held in place with a circular nut hidden behind a rubber “debounce” washer. The same tool that I used to remove the valve nut on the Apache airguns and the pneumatic Plainsman was also the perfect tool for this pistol too. Once this was removed, along with the valve locating grub screw, the valve body was gently tapped out using a wooden dowel from the CO₂ capsule chamber. 

If you are planning to use the disassembled photograph for reference when stripping your CO₂ Plainsman, beware that it has a couple of errors and omissions. First, the trigger sear is shown the wrong way round. Importantly, what looks like a spring top hat should be on the CO₂ capsule side of the spring rather than the valve side. The valve body will not close completely if it is fitted as shown in the photograph. Lastly, there are two valve sealing washers. One is shown to seal the two halves of the valve body together, but there is one more that seals the piercing pin section of the valve body to the steel CO₂ capsule tube.

The rest of the pistol is comprised of two major parts which are the grip frame that houses the trigger housing and the pressure chamber tube which contains the valve, barrel, hammer and bolt probe housing. The design is essentially the same as the pneumatic Plainsman in this regard. Just like the pneumatic Plainsman, the grip and trigger housing is cast alloy and is attached to the pressure chamber with a screw in front of the trigger guard. However, unlike the pneumatic Plainsman, it doesn’t have a pin to secure it at the rear of the grip frame. The pressure chamber consists of two parts. A blued steel tube that houses the CO₂ capsule and a cast alloy section at the rear that houses the valve, hammer, barrel and bolt probe. It appears that the alloy grip and rear section of the pressure chamber may have originally been painted either satin or gloss black.

The paint was stripped from the alloy using paint stripper and wire wool. It came off remarkably easily and the metal underneath was left undamaged. The blued CO₂ chamber was in very good condition considering its age I decided not to re-blue it. Any minor damage was repaired with bluing gel and later it was masked off in preparation for painting of the alloy section. The rear sight had also been painted. After stripping, a blued steel finish in perfect condition was revealed! The condition and finish of the cast alloy sections were found to be near perfect and so there was no need for any further preparation before painting.

Painting the pistol was a two-step process. A couple of coats of grey etch-primer was applied followed by a number of light coats of satin black automotive paint. The barrel was not a painted item that I could tell, instead, it appears to be blacked brass. The condition of the barrel was reasonable and so I decided to leave it alone.

The pistol was reassembled after allowing the paint to fully dry for a week. A month or so later I painted the stamped letters by applying a wash of off-white enamel paint and allowing it to run into the lines. This was something I had learnt from my days of scale model painting. The wash was left overnight to harden before removing the excess with enamel thinners on a cloth. Removing the excess can be a nerve-wracking and delicate process. It is important to wipe and not rub or the black paint could also be removed requiring the whole process of stripping and painting to be started over. After a couple of wipes, it is wise to allow the paint to harden once again overnight and then repeat. This process can take a couple of days to complete.

Similar to its pneumatic sibling, the CO₂ Plainsman appears to be very well made. It has a blued steel CO₂ chamber in keeping with the pneumatic Plainsman. But, rather oddly, it has a brass rather than a steel barrel. The CO₂ Plainsman pistol was also available in both .177 and .22 calibres although today, .22 calibres are more commonly found. I have only seen one .177 calibre CO₂ Plainsman which suggests that they may not have been produced in as many numbers as the .22 variant. There also appears to be two sub-variants of the CO₂ Plainsman as some are marked with the calibre on the right-hand side of the breech housing and some are not. Also, some that are marked with the calibre are also marked “C” perhaps for CO₂ whereas others are just marked “22” or “177”. It is possible at some stage it was decided not to stamp the frames with the calibre to reduce costs on the production line as the barrels may have been interchangeable.

The pistol measures approximately 24 cm (9½”) long with a 13 cm (5″) brass rifled barrel. It weighs 888 grams (1lb 15oz) without the CO₂ capsule fitted. I wonder why a brass barrel was used when the pneumatic was steel? I suspect it was either due to cost savings or the availability of barrels.

According to an example that appeared in an auction in November 2011, an optional target barrel was also available for the pistol. The barrel measured approximately 20 cm (7¾”) long and would have extended past the end of the pistol by about 7cm (2¾”). [4]

The sighting equipment is similar to the pneumatic model with a fixed blade front sight and an adjustable rear sight. The fixed front sight normally has a ring attached that would fit over the steel CO₂ capsule chamber. Unfortunately, this example as with many others appears to have had the ring broken off at some stage. I find this strange considering the quality of construction of the pistol is very high. It would be interesting to hear any first-hand accounts regarding whether any of these pistols left the factory in this condition.

Charging the pistol is achieved by removing the cap at the front of the pressure chamber using a coin. An 8g CO₂ capsule is loaded neck first and the cap is then screwed back on. A single o-ring (16mm OD x 2.5mm cross-section or size R11) is fitted to the cap to seal the chamber. If you intend to replace this o-ring, it is advisable to use a polyurethane o-ring as Buna-N or Viton o-rings will expand to twice their size when exposed to high concentrations of CO₂ gas. Having said that, I have used Buna-N o-rings without problems in this pistol. I noticed a little swelling of the o-ring after seventy shots at low power. Perhaps if you leave a full or partially full CO₂ capsule in the pistol for a few hours you may run into difficulties. Either way, Buna-N can be used as a temporary replacement if necessary.

Unlike modern CO₂ pistols, the action of screwing the cap does not pierce the CO₂ capsule. Instead, this is achieved when the pistol is first fired as the hammer forces the piercing pin into the capsule. As the chamber is not fully pressurised, the first shot lacks power. Therefore, to prevent a jam, it is recommended to first dry fire the pistol without a pellet loaded.

A pellet is loaded by first turning the bolt probe anti-clockwise to align the lock pin with the bolt probe slot. The bolt probe is then withdrawn, exposing the breech where a pellet can then be inserted. A nice feature of this pistol is a small shelf just in front of the breech where a pellet can sit without slipping off. When the bolt probe is pushed forward to close the breech, the pellet is pushed into the barrel the correct distance past the transfer port. However, unlike the Schimel gas pistol of the same period, the design of the bolt probe has no provision for a sealing o-ring. Therefore, it isn’t perhaps as efficient as it could be.

To cock the pistol, the hammer knob is pulled backwards until the hammer engages on the trigger sear. One reference suggests that the pistol has two power settings by either half or full cocking. However, there actually is only one cock position available on the pistol. This has also been confirmed from other examples of other fellow collectors. This is further backed up by a close examination of the hammer which shows that no provision was made for a half cock position. [5]

However, the instructions clearly state that the power can be adjusted and is in fact part of the CO₂ cartridge piercing procedure. On close inspection, I found that the hammer knob can be unscrewed from the hammer weight. By unscrewing the rod, the amount by which the valve opens can be controlled and thus provides some control over the power generated by the pistol. The instructions state “Be sure that the power control knob on hammer shaft is screwed in on full power when puncturing cylinder, then back off on knob to the desired power“.

In practice, it is easier to use in two power settings of either full or half power. Full power is a simple matter of screwing the power adjuster fully in. Half power is a little harder to explain. If the adjuster is unscrewed too much, it won’t open the valve at all. I found that as the adjuster is unscrewed, the hammer rod would move in towards the valve. It stops moving inwards at the point when the power adjuster just makes contact with the valve stem. There is a rubber washer that cushions the blow of the hammer weight when it is released. This acts as a debounce mechanism to stop the hammer from bouncing the valve open. In turn, this improves the gas efficiency of the pistol. Without this washer, setting the pistol to low power as I have described would not allow the pistol to fire. But the force of the hammer is enough to squeeze the rubber just enough to allow the valve to open. You can see from the low power chart how ragged the power curve is. I expect that this is due to the flexible nature of the rubber washer making each shot slightly inconsistent. Perhaps if the adjuster rod is screwed half or a whole turn, the curve may be smoother as shown on the full power chart.

Similar to the pneumatic Plainsman, there is no safety mechanism. This isn’t a surprise as the design of the two pistols are identical except that one has a pump and the other a CO₂ cartridge powerplant. But also there really isn’t a need for a safety. As long as the hammer is not cocked, the pistol is inherently in a safe condition.

The trigger feels identical to the pneumatic version which is remarkably good. Just like the pneumatic version, there is no first stage and a very slight squeeze releases the sear.

In the full power configuration, the power of the pistol averages at 5.38 fpe or 411 fps over the first ten shots with a 14.3 gr .22 calibre pellet. There are approximately eighteen usable shots between 5.5 and 5 fpe before the power rolls off as shown on the high power chart. The low power configuration yields an average of 3.55 fpe or 334 fps over the first forty shots before it dips under 3 fpe. The pistol continued to shoot a total of seventy pellets on one 8g cartridge in the low power configuration. It still appeared to have another ten dry shots before it was empty!

In summary, this is a lovely, no, a superb, 60-year-old CO₂ pistol and was one of the first airguns to use the miniature CO₂ capsules. The power is very good for a sub 6 fpe airgun with up to twenty full power shots from a single capsule. When set to high power, there is a noticeable kick or recoil. Combined with how loud it is at high power brings a shock and quite a surprised smile to the shooter’s face. It’s certainly a head-turner at the range!

It’s been an absolute pleasure to restore this old girl. So much so I think this pistol has found its way into my top ten favourites and is likely to be a regular appearance at the range!

And so it is time for me to once again say….. until next time, happy shooting!

Jimmie Dee  

References:

1. The Challenger Arms Corporation Plainsman Pneumatic Air Pistol (1949-1951), Jimmie Dee’s Airguns
2. The Vintage Airgun Gallery – Challenger Arms Corporation – Plainsman CO2 Pistol
3. Lot 156, Guns. Quack Machines. Antiques Auction, Cady Auction & Appraisal
4. Lot 1169,  Reata Pass Auctions, Massive All Gun Auction, Challenger Arms, Plainsman Air Pistol, Cal .22
5. Gas, Air, and Spring Guns of the World, First Edition by W.H.B. Smith