Winning the Cold War

Winning the Cold War

The battle between CO2 and the thermometer Part 3 Part 2 Part 1

By Dennis Adler

Back in the Old West guns had to work no matter what the temperature. With CO2 powered Peacemakers it isn’t quite as cut and dried. Depending upon the gun, CO2 can be problematic at temperatures below 50 degrees (CO2 works best at between 70 and 80 degrees), but as this cold weather test will show, there are always exceptions. (The custom 5-1/2 inch Colt holster by Chisholm’s Trail is now available from Pyramyd Air)

Using Nitrogen in place of CO2 has its benefits if the temperature is well below minimum for CO2. But there is another question, CO2 super cools when rapid firing is involved, this could be fanning a single action, like the 5-1/2 inch Umarex Colt Peacemaker or using a select fire semi-auto, such as the Umarex Model 712 Broomhandle Mauser. I have put these two classic 19th century handguns (the Broomhandle was initially developed in 1895), into a 21st century battle to see how well Nitrogen survives the ultimate test of an air pistol.

Another issue with CO2 is fanning a Single Action. This can super cool the CO2 by rapid firing which causes velocity to drop and accuracy to decrease. Again, this is the norm but not always the outcome.

I am going back to the first gun that gave me fits when the mercury dropped well below the minimum for CO2, a BB firing Umarex Colt Peacemaker. The second part of this test is two fold, a different type of semi-auto than the Tokarev TT to see how well CO2 performs in freezing temperatures with a self-contained CO2 BB magazine, and how well Nitrogen performs on full auto, or fanning a sixgun. CO2 has a quick drop in velocity (and accuracy) when a pistol is fired rapidly. Nitrogen should not, but how many rapid fire shots can you get on just 1.8 grams vs. 12 grams?

Pyramyd Air now has a complete line of Chisholm’s Trail Single Action holsters for the 7-1/2 inch and 5-1/2 inch Peacemakers, Schofield and Remington revolvers. You can find all of the custom made Chisholm’s Trail holsters, as well as one for the Broomhandle Mauser Model 712, by typing Chisholm’s on the Pyramyd Air product search bar.

The Cold Test

The weather for this series of tests has been most inhospitable, snow followed by freezing rain. Today, for this final round of cold weather testing with the Umarex 5-1/2 inch Colt Peacemaker and Model 712 Broomhandle Mauser, the temperature is 25 degrees. For the Single Action test I used Umarex steel BBs and Sig Sauer CO2 cartridges with a target board set out at 21 feet firing half the test single handed, almost the entire second half double handed, fanning a dozen rounds. After firing 72 shots I chronographed the gun, which still delivered an average velocity of 350 fps. I shot another dozen rounds with the same accuracy as the first six, at which point I saw no logical reason to duplicate the test with Nitrogen since it can not deliver the same total number of shots. I went back and chronographed the Peacemaker one last time and it averaged 353 fps. Once again I am surprised by how well CO2 has worked in this Peacemaker at 25 degrees. I fired a total of 102 shots on one CO2 cartridge all within 350 fps to a high of 389 fps.

Once again I am surprised by how well CO2 has worked at below freezing temperatures. With the Umarex Colt Peacemaker I fired a total of 102 shots all within 350 fps to a high of 389 fps. This far surpasses my earlier tests with the Single Action models which did not even come close to 50 rounds at below freezing temperatures. The most impressive part of the test was the target, which includes a dozen fanned shots from 10 feet and the balance fired single handed and with a two handed hold. I carried a dozen loaded shells and left the gun outdoors while I reloaded the shells indoors. The area that is circled on the target board contains over 40 shots at 0.75 inches. It isn’t often .177 caliber BBs blow entire portions out of a cardboard target. The Umarex was that consistently accurate and maintained velocity at a temperature of 25 degrees. 

At 28 degrees the Model 712 performed well delivering two magazines fired single action and one on full auto before the CO2 was expired. Velocity was beginning to drop off in the middle of the third magazine, and while still fairly accurate, penetration of the cardboard turned into dents rather than holes toward the end. Nevertheless, there was a fairly tight concentration of shots for this gun at 21 feet.

Switching to Nitrogen for the final test, velocity was off the chart with an average of 400 fps, compared to the usual “maximum velocity” for the Model 712 of 360 fps. The action was working even faster on full auto. Only a second or so and the Nitrogen was done and the magazine empty. If you want a fast, high velocity run on full auto, (temperatures not withstanding) the Nitrogen will give you your money’s worth in the Model 712.

Shooting the Mauser in the same temperature I got two 18 round magazines off single action and a third feathering the trigger on full auto. That exhausted the CO2 in the magazine. So here a total of 54 shots. I switched to the Leland Nitrogen and repeated the test. Nitrogen will only run one magazine on semi auto but it runs it hot at an average of 400 fps. I ran a second magazine on full auto and Nitrogen sends that bolt back with enough kick that you know this gun is running through ammo. I definitely got my $2.50 worth out of that magazine load.

Blowback action semi-autos and select-fire pistols can be a drain on CO2 under the most ideal temperatures. The Umarex Mauser Broomhandle Model 712 uses separate self-contained CO2 BB magazines, leaving the CO2 more exposed to the ambient temperature since it does not have the benefit of being inside a pistol grip held by a warm hand. The metal magazine also absorbs cold more readily than the plastic grips on a traditional pistol frame housing the CO2. (The Model 712 holster from Chisholm’s Trail is now available from Pyramyd Air in black.)

The concentration of shots is pretty tight for the Mauser. This is one target shot with both CO2 and Nitrogen.

At the end of the day, Nitrogen will do a great job in cold temperatures but in the overall scheme of things, with the right air pistol, at least the three I chose, CO2 will hang in there just as well, not as long as it would in optimum temperatures, but longer than Nitrogen. And the bottom line after this entire series…nothing is faster on the draw or more accurate fired single action at 21 feet, than a Peacemaker. The Tokarev comes in a close second and the Broomhandle a distant third. Which of the three is the most fun to shoot? All of them!

8 thoughts on “Winning the Cold War


  1. Nice holsters. I don’t know if Chisholm makes it , but one of my favorite holsters is the John Wesley Hardin version with six bullet loops. I have a pair from triple k , last I looked El Paso Sadddlery made one . In 357 they work nicely for theUmarexPeacemakers. Veryhandy.


  2. The black leather Chisholm’s Trail holster for the the Mauser just needs a companion holder for the Mauser magazine. Does Chisholm’s Trail have the magazine holder as well?


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