Colt Python pellet shell swap out

Colt Python pellet shell swap out

Dynamic principles collide

By Dennis Adler

It is one of history’s most desirable .357 magnum revolvers, the Colt Python, and with the Umarex CO2 version this legendary revolver becomes vastly more affordable to own and nearly as much fun to shoot as the .357 magnum model. As designed by Umarex and Colt, the Python CO2 model comes with six front loading BB cartridges and a speed loader.

My recent tests of rear-loading pellet-firing shells in smoothbore barreled revolvers like the Remington Model 1875 and Schofield has raised an interesting question. What prevents you from using pellet firing shells in other smoothbore BB shell revolvers? Firing lead pellets down smoothbore steel barrels only leaves behind a little leading that is easily cleaned and does no harm (as opposed to steel BBs down a rifled barrel). A 4.5mm lead pellet weighs 7.0 gr. (unless you use a lighter weight alloy pellet) compared to the average steel BB which is around 5.1 gr. Worst case scenario you lose a little velocity, but, if the cartridge-loading smoothbore BB gun uses front-loading cartridges, and you change that dynamic to rear-loading pellet shells, (which have proven to produce higher velocities) you could get some surprising results. For the pellet shell swap out I have examined a number of smoothbore BB revolvers for compatibility and there are almost none (with the notable exception of Umarex Colt Peacemakers but since Umarex makes both smoothbore and rifled barrel models, its kind of a moot point). The one smoothbore revolver that really needs this swap out is the Umarex Colt Python, an extremely good gun to shoot but lacking in decent velocity for a revolver (compared to a blowback action semi-auto).

The question that has been raised since the advent of more pellet and BB cartridge firing models is the possibility of swapping out pellet cartridges for smoothbore BB models. The answer for some of these guns is yes you can, a few are available with both BB and pellet loading cartridges, while others become a game of finding the right round. Pictured are the Umarex Colt Python BB cartridge (left) the Crosman Remington Model 1875 rear-loading pellet cartridge, Colt Peacemaker rear-loading pellet cartridge and new Bear River Schofield rear-loading pellet cartridge. Only one pellet round will work in the Umarex Colt Python, the silver Colt Peacemaker cartridges.

Pellet shell swap out for the Python

 It goes without saying that most of you do not have access to multiple guns and multiple pellet firing shells to try a pellet shell swap out, so I have researched currently available pellet-firing shells. First, what doesn’t work and why. The Umarex Colt Python uses a front loading BB shell with a specific diameter rim, and the rim size is critical to the shell fitting the ejector. Of course, you really don’t have to use the ejector on a CO2 revolver since there is no possibility of shell case expansion after the round is fired. In most instances even with real cartridge revolvers, spent shells will just fall out when you open the cylinder and rotate the gun back, but sometimes a shell case will swell just enough to need a little push, and thus the need for an ejector. With a cartridge-loading CO2 revolver just tipping the cylinder back will allow the empties to fall out; ejectors are for authenticity but not of necessity. But there’s more to it than that. If the rim diameter of the pellet or BB shell is too small to catch the edges of the ejector, it will be sitting a fraction of an inch lower in the cylinder and thus create a slightly greater gap between the back of the cartridge and the CO2 valve in the recoil shield. Basically the same problem as too much cylinder gap to the barrel’s forcing cone, but on the other end. Either could cause a slight loss of efficiency by allowing air to escape.

Here the Python is loaded with its front-loading BB round at far right (marked UX on the rim), below that the 4.5mm Remington Model 1875 rear-loading pellet cartridge, next the new Schofield round and at far left the silver Colt Peacemaker round. They all appear to fit in the cylinder, but…

To be certain a rear-loading pellet cartridge will work in the Python it has to have a rim diameter that fits the ejector. Because it isn’t that apparent when you load a shell into the chamber, push the ejector rod and if the shell stays in the cylinder or falls off the ejector as it rises, the rim is too small.

…only the Umarex rounds work, the front loading BB shell and rear-loading Peacemaker pellet round, the other two (as well as the ASG Dan Wesson rounds) all fall through the extractor when it is pushed to remove the shells. This can be problematic in a couple of ways and only the Colt Peacemaker pellet shells should be tried in the Python.

To examine the available rear-loading pellet cartridges I began with pellet shells from last week’s Remington and Schofield test, but they proved too small and dropped through the ejector. Next I tried the ASG rear-loading pellet shells for the Dan Wesson Model 715 pellet revolvers, and surprisingly they were also too small for the Python’s ejector! After the first three shells, it looked like a dead end unless Umarex decides to make a rear-loading pellet shell for the Python, and then I grabbed six of the silver rear-loading pellet shells for the rifled barrel Umarex Colt Peacemakers. They fit! So, if you have a rifled barrel Peacemaker you have at least six rear-loading pellet shells that will fit in the Python’s cylinder. If you have a Python but no Peacemaker, you can buy the Peacemaker pellet shells separately from Pyramyd Air.

I have to tell you, Umarex does not recommend swapping out shells between guns, shooting pellets through its BB models or BBs through its pellet models but, as has been proven with both the Schofield and Remington smoothbore single actions, you can do it. As for using Colt Peacemaker pellet rounds in the Python they fit the cylinder just fine but are not designed for use in the Python’s speed loader. Win one, lose one.

With six Peacemaker rear-loading pellet rounds chambered, the Python is ready to break some records for velocity and accuracy with Sig Sauer alloy pellets.

Python on pellets

To retest the Python and set up a baseline, I chronographed velocities with the front loading BB cartridges using Umarex .177 caliber steel BBs. Average velocity was 364 fps with a high of 370 fps, and a low of 348 fps for six consecutive shots. Switching to the rear-loading Peacemaker pellet cartridges with Meisterkugeln Professional line 7.0 gr. lead wadcutters, average velocity from the Python’s 6-inch (5.75 inch internal length) smoothbore barrel dropped to 315 fps with a high of 322 fps. This was not surprising given the increased grain weight. I then re-shot the test with Sig Sauer Match Ballistic alloy pellets which weigh 5.25 gr., just 0.15 grains more than a .177 caliber steel BB. The top velocity with the Sig Sauer alloy pellets was an impressive 395 fps with average speeds of 387 fps, 383 fps, to a low of 367 fps. This is a noteworthy increase, not only over the Meisterkugeln lead pellets but over steel BBs as well.

None to shabby with .177 caliber steel BBs, the Python delivered a best six shots from 21 feet measuring 1.125 inches.

 On Target

The first test was shot with Umarex .177 caliber steel BBs and my best six shots measured 1.125 inches. This shows the inherent accuracy of this gun at a mid-range distance of 21 feet. The switch to the Peacemaker rear-loading pellet cartridges loaded with Sig Sauer alloy pellets had already shown a marked increase in velocity and at 21 feet the Sig wadcutters gave me a best 6-round group of 1.0 inches with two shots overlapping and a pair in the bullseye. Not a dramatic increase in accuracy but a big boost in velocity which will take this gun out to 10 meters with alloy pellets. I shot the final test at 10 meters with the Sig alloy wadcutters and got a best 6-round group measuring 1.25 inches, which is 0.25 inches better than with steel BBs at 10 meters (Airgun Experience No. 68).

Best six from the Python at 21 feet using Sig Sauer alloy pellets was 1.0 inches with two shots overlapping and a pair in the bullseye.

If you are also wondering if alloy pellets are easier on the gun, the answer here is also yes, since alloy pellets will not leave lead fouling in the barrel, so cleaning is a lot easier. More costly for certain, with a tin of 500 Sig Sauer pellets running around $35 compared to 500 Meisterkugeln lead wadcutters for $12.

Stepping back to 10 meters with the pellet firing cartridges I managed a best six shots in the X of a B-27 silhouette target covering 1.25 inches. That is the best I have ever done with the Python at 10 meters. (To be honest I can do better with the 7-1/2 inch Peacemaker at 10 meters, but that’s not the point of this story…)

The Takeaway

 Is the Python that much more accurate with pellets? In a game where first and second place finishes are measured in fractions of an inch, it is, and if you are into target shooting and want to get the most performance from the Python, load it up with Colt Peacemaker pellet cartridges, alloy pellets and shoot away. You’ll get the results you’re looking for.

 One quick note

I want to thank all of you for your feedback on articles over the past year since the Airgun Experience began. Reader comments can and often do lead to articles that explore your questions, such as this one about using pellet-loading cartridges in smoothbore BB revolvers. This exchange of ideas works well because Airgun Experience is done in the style of a magazine article with extensive photography and longer text and captions. In a print magazine when a reader has a comment or a suggestion about an article or a gun, it usually comes in the form of an email, just like it does here, only no matter how fast we respond in print; at best it takes two to three months from the time an article is done until the magazine hits the newsstands. With Airgun Experience, we can take your question or suggestion and turn it around into an article within a couple of days. So keep your comments and questions coming! It’s all part of the experience.

23 thoughts on “Colt Python pellet shell swap out

  1. As expected a nice increase in accuracy. Was surprised at the velocity with the 7 grainers since with other revolvers they shot higher with pellet cartridges,still nice increase in accuracy and velocity with the alloy Sigs. Too bad they are as or more expensive than 22 rimfires. Maybe if this trend continues, someone will offer light , 5-5.5 grain plain or 1 77 rifled pellets. Will try this in my Python and see what I get accuracy wise. Thanks for the write up. Another reason for manufacturers to standardize on pellet cartridges.


  2. while some alloy pellets are expensive ,I found some that are reasonable and if you factor in buy 3 get one , not too bad, H&N for example 5.56 wadcutters , lead free 500 /$25 ,will probably pick some up and reserve them for the smooth bores


  3. Did the deed on the alloy pellets ,tried a few brands and with website discount and shipping , got a total of 900 pellets for $42. will run some accuracy tests over the weekend when they arrive



    • If they offer a rifled barrel Python, I would like to see more than a rifled barrel on the current model. It should be more like a Dan Wesson 715 ,with the high polish blue finish as well as nickel. It should be an exact replica of the Python frame , not the overly high frame on the current model. It should have a white outline rear and a thicker red ramp front sight. Lastly , barrel lengths of 2/1/2 , 4 and 6 inches



  4. A little over 20 percent increase in velocity for
    a slightly more than 20 percent decrease in pellet weight, is this a rule? As far as rifled barrels go, I wonder if the Umarex Wesson revolver develops enough power to expand the skirt of the pellet in order for it to engage the rifling. I mean 315 fps seems pretty anemic.


    • Do you mean the ASG Dan Wesson? Yes it does and it is pretty darn accurate. I’d like to see some higher velocities as well, but 315 fps gets the job done. Grain weight has a lot to do with velocity, so you might consider alloy pellets if you want more fps. They work great in rifled barrel models and smoothbores alike.


  5. That brings up a another question my Crosman 2240 shoots 14 grain pellets at over 400 fps so why aren’t these Umarex revolvers spitting those much lighter 177 pellets at a much higher velocity.? I mean the Colt ,Remington and Wesson revolver barrel lengths are similar to the Crosman 2240, and none use any co2 to cock the action,so why aren’t the velocity’s higher?


    • These are my thoughts on that question. Your Crosman 2240 has a rubber O-ring on the end of the bolt to seal the back end of the barrel after you insert your pellet. There are no other “breaks” in the 2240 barrel. Consequently none of the CO2 can “leak” out; all of the CO2 is focused on the pellet shot to push it out of the barrel.

      On these revolvers with the pellet / BB shells, there is a spring loaded “extension” on the barrel in front pressing against the front of the cylinder and a similar “extension” doing the same on the back of the cylinder. The goal is to seal as much as possible to the shell to minimize loss of CO2 and loss of power. But remember, these are not “air-tight” seals; they leak a little.

      I could be completely wrong, but my explanation seems reasonable.


    • You have mentioned your Crosman 2240 before and it is a fine pistol, but you are comparing a single shot, bolt action design with a revolver. This is not a fair comparison, a bolt action design creates a totally closed environment for the pellet (as it does for a cartridge in a bolt action rifle or pistol), while a revolver has separate components, the cylinder and barrel, and there are minimal gaps between those two as well as the space between the back of the cartridge and the recoil shield/firing pin or with a CO2 pistol, the valve. Its not exactly an apples and oranges kind of difference but you can’t really use the 2240 as a comparison with a pellet-firing revolver.


  6. Thank you, Dennis. This a great read. I don’t miss a one. I am a C 02 pellet revolver fan and was wondering if you had any thoughts on the Gamo PR 766 pellet revolver.


    • It’s a different system using the rotary pellet magazine that loads at the back of the cylinder rather than individual pellet-firing cartridges, so authenticity is not there, compared to the Umarex S&W TRR8, for example. I like the Gamo (and Umarex has a similar model as well). The big advantage for the Gamo RP 766 is, of course, the rifled barrel, which the Umarex S&W TRR8 does not have. It is a mater of preferences between total authenticity and a little more exotic looking and accurate gun from Gamo. I like it.


  7. Yes I thought there must be some sort of leakage. And the more I think about it creating a perfect seal would probably compromise the very realistic workings of the Umarex revolvers. Because of Airgun Experience and it’s very knowledgeable readers I’m learning how little I truly know about airguns.



  8. The Peacemaker shells are the first air gun cartridges that don’t fit in a medium frame357 speed loader. I don’t have one handy but I wonder if they will fit in a S&W Nframe HKS speed loader.


Leave a Reply