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Education / Training Crosman 2400KT CO2 Air Rifle – Part 10

Crosman 2400KT CO2 Air Rifle – Part 10

by Tom Gaylord
Writing as B.B. Pelletier

Today we have something special. This is Part 10 of an ongoing guest blog from reader Hiveseeker, but his report today is so big that I had to break it onto two parts. The second part of this report will run tomorrow as Part 11. He continues to research this subject that fascinates both him and many other readers.

This is about the Crosman air rifle he really enjoys. If you’d like to write a guest post for this blog, please email me. Now, over to you, Hiveseeker.

Crosman 2400KT CO2 Air Rifle – Part 10
The great Crosman 2400KT barrel shootout
By Hiveseeker

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9

This report covers:

  • Barrel variable
  • Barrel challenge
  • Why only .22?
  • The great 2400KT barrel shootout
  • 24-inch barrel — 13 foot pounds!
  • 7.5-inch barrel
  • 10.1-inch barrel
  • 14.6-inch barrel
  • 18-inch barrel
  • That’s it for today

Crosman 2400KT
Meet the Chimera! It is a Crosman Custom Shop 2400KT CO2 Air Rifle with 24” Crosman .22 barrel and shoulder stock. Cost as shown was $108 plus $24 shipping. This gun was named after a mythical Greek monster that was a motley assembly of different animal parts. That’s exactly what I plan to do with this gun and an assortment of barrels!

In this blog we will take a detailed look at how barrel length affects velocity in the Crosman 2400KT CO2 Air Rifle . However, this information should apply equally to modding a Crosman 2240, 2250, Sheridan 2260 MB rifle, or 2300KT. From my research, all these barrels should be interchangeable. Note that all these velocities were obtained using the Crosman Custom Shop power valve, which adds about 90 f.p.s., compared to the standard Crosman valve.

Barrel variable

When you purchase a 2400KT from the Crosman Custom Shop, the single most important choice you make is the barrel. While you can choose from a wide selection of grips, muzzle brakes, trigger shoes, and sights, the barrel is the only option that affects how the gun actually performs. And, as we uncovered in Part 9, it also influences which valve the Crosman Custom Shop installs in your custom gun.

I was surprised when my original two 2400KTs — a .177 and a .22 — had identical velocities. A .22 pellet is twice as heavy and shouldn’t be traveling the same speed! Several blog comments attributed the high .22 velocity to that gun’s 18-inch barrel. That’s certainly part of the equation, but all my research indicated it was more than that, and in Part 9 we found that an extra powerful Custom Shop valve in that gun was adding 90 fps. This extra boost appears to be enough to make one 2400KT shoot a .22 pellet just as fast as another 2400KT shoots a .177 pellet . But the comments were also correct: In a CO2 gun a longer barrel adds velocity. The question was, how much?

Barrel challenge

I spent weeks scouring numerous Crosman fan and modding sites for barrel length and velocity data on the 2400KT . I quickly found that few modders are interested in posting stock velocities. What little stock data I could find usually compared only two barrel lengths, or was for .177. And, as other forum browsers also noted, data from different sources was sometimes inconsistent or even contradictory. I did find some thorough test data on the stock Crosman 2240 in a GTA (the old Gateway to Airguns ) forum post on 6 different barrel lengths for the 2240. However, I still needed to know what the power valve could do in the 2400KT.

I finally realized that I would need to get my own answers. I happily relented and ordered a 2400KT with a 24-inch Crosman .22 barrel, the maximum available length. That’s the gun pictured above. A second order of parts added every Custom Shop .22-caliber barrel I didn’t already own. When my boxes arrived and the dust settled, I was ready to start swapping barrels and testing velocities!

Why only .22?

By far the primary reason Crosman owners mod their guns is to increase velocity. Most are trying to increase velocity in order to hunt. All other factors being equal, the same CO2 gun will generate more muzzle energy (hunting power) with a .22 pellet than with a .177 pellet. I therefore limited the focus of my testing to the maximum achievable muzzle energy, and that meant staying with .22.

Here is the Chimera with installed 24 inch barrel, and the 14.6 inch, 10.1 inch, and 7.5 inch barrels I ordered for testing. I was ready to roll!

The great 2400KT barrel shootout

I ordered the Chimera with the 24 inch Crosman .22 barrel, but I also purchased and installed 14.6 inch, 10.1 inch, and 7.5 inch Crosman .22 barrels for testing. I already had data for a Crosman 18 inch .22 barrel on another functionally identical 2400KT.

I ended up doing all my velocity testing with the Benjamin Discovery Hollowpoint. It’s a 14.3-grain middleweight, a Crosman pellet that works well in many Crosman guns, and when I velocity tested five different Crosman pellets in my first 2400KT this one landed right near the middle as a good representative.

Below are the velocity curves from these stock Crosman barrels. All testing was completed at 84 degrees F using the Chimera, except for the 18 inch barrel for which I already had data at 88 degrees F from another 2400KT. (Be aware that CO2 velocities will be slightly lower at cooler temperatures. Detailed testing by Stephen Archer found that for .22 guns velocity can vary 1.8 to 2.0 fps for each degree F.) I waited 90 seconds between shots to allow the CO2 cartridge and gun to warm back up, which yielded slightly higher velocities and also better simulated hunting conditions, where shooting opportunities usually do not occur in rapid succession.

barrel graph

The first thing to notice about this graph is how similar in shape all the velocity curves are (except for the 24 inch barrel — hold that thought). Although the velocities obviously vary, the performance curve was very consistent from one barrel to the next. All the barrels gave about 20 to 25 full power shots before velocity began to drop. The velocity lines stop at 400 fps because I found that, below that velocity, accuracy decreased rapidly and there was no practical reason to test further.

The second thing to notice I’ve already mentioned — the velocity of the 24 inch barrel drops off more steeply than the others. I believe this barrel is long enough that, once the CO2 starts to become depleted, barrel friction begins slowing the pellet down quickly, giving a steep but almost perfectly straight slope. The other barrels are too short to exert a similar effect above 400 fps.

24 inch barrel — 13 foot-pounds!

I’m going to start out of order with the longest barrel, and tell you about my first test on the stock Chimera as it arrived out-of-the-box with the 24 inch Crosman barrel. This gun surpassed all my expectations! The Chimera clearly shipped with what I call the power valve, the more powerful of two different valves that the Custom Shop uses. (See Part 9) From my own purchases, 2400KTs with 18-inch and 24-inch Crosman barrels ship with the power valve, and 2400KTs with Lothar Walther barrels ship with the lower velocity target valve.)

For the first 10 shots I got an average velocity of 617 fps with the 14.3 grain Benjamin Discovery Hollow Point. At this velocity the barrel generated a muzzle energy of 12.09 foot-pounds, which just meets the minimum recommended 12 foot-pounds for hunting (see The advantages of hunting with an airgun).

This velocity actually exceeded B.B.’s Crosman 2240 conversion to air, in which he got 588 fps with the identical-weight 14.3-grain Crosman Premier using a 14.5 inch barrel. But you have to go to ridiculous (barrel) lengths to beat it!

In CO2 guns heavier pellets usually generate higher muzzle energy, and when I tried the 25.39 grain JSB Exact Jumbo Monster I got an average velocity of 485 fps and 13.25 foot-pounds! This appears to be the maximum performance limit on a stock Crosman 2400KT, which does make this gun a hunter. This barrel was too long to be practical for my needs, but I sure was sad when it was time to remove it!

7.5 inch barrel

The 7.5 inch barrel was LOUD — a sure sign that excess CO2 was being wasted. I actually had to wear ear protection when shooting indoors! Average velocity for the first 10 shots was 464 fps, close to the listed spec of 460 fps for the Crosman 2240 which has the same barrel. Considering that the Chimera has the power valve but here gets less than 30 shots over 400 fps, you know that much of the CO2 is only going toward making noise.

7 inch barrel
Well, you can see why the 7.5 inch barrel is not offered in the 2400KT line! This was a 2300KT barrel, but from what I had read all the Crosman CO2 gun barrels are interchangeable.

These numbers also give us the maximum velocity spread on our barrel test right up front: 153 fps over a range of 16.5 inches of barrel length. This was MUCH more than I expected! Crosman Customer Service had told me to expect about a 50 fps spread across all the available Custom Shop barrels. B.B. found an almost identical 52 fps spread in his report, How barrel length affects velocity in a CO2 rifle. However, this range of barrels — 7.5 to 24 inches — is not actually available on any one gun in the Custom Shop. The 2300KT offers 7.5 to 14.6 inch barrels, while the 2400KT offers 10.1 to 24 inch barrels. And B.B.’s test covered 13 to 20 inches of barrel length. It makes sense that testing a wider range of barrel lengths will yield a wider range of velocities. In particular, including the 7.5 inch barrel and the 24 inch barrel at the extreme ends of the scale increased the total velocity spread by a full two thirds (51 fps and 59 fps respectively, as you’ll see shortly). So that’s the reason for such a broad velocity spread. Subtract the two extreme barrels, and the velocity spread drops to 43 fps — pretty darn close to what Crosman told me and to what B.B. found. These numbers are important, and we’ll discuss them in more detail after we cover the rest of the barrels.

10 inch barrel
Although I’m showing you the 10.1 inch barrel now, this actually ended up being the final form of my Chimera: A compact pistol plinker with significantly more power than a 2240. I swapped the shoulder stock for 2240 pistol grips and installed a red dot sight.

10.1 inch barrel

This was actually the barrel that I tested last, and it represents the final phase of my morphing Chimera. This barrel was a little louder than all the others except the 7.5 inch barrel, again an indication that CO2 is being wasted. However, noise was only moderately loud when shooting outdoors and I actually think the ported muzzle brake helped reduce it. With this barrel velocity jumped to 515 fps, a 51 fps increase over the 7.5 inch barrel. Even though I know that I’m still wasting CO2, this barrel gives me about 25 full power shots over 500 fps and a total of almost 35 accurate shots over 400 fps. With a red dot sight dropped on top, using UTG 11mm to Weaver adaptors, this is my fun backyard plinker which has a significant velocity boost over a 2240. Note that the shoulder stock was replaced with 2240 pistol grips.

14.6 inch barrel

This barrel produced a moderately loud report and provided a velocity of 543 fps, a 79 fps increase over the base 7.5 inch barrel. For many shooters, this will be the maximum practical barrel length, especially if you order your 2400KT with pistol grips rather than a shoulder stock.

18 inch barrel

The data shown for the 18 inch barrel is from my original HiveSeeker which you have seen regularly in my previous blogs. The gun is identical to the Chimera except for cosmetic color differences. However, it did behave slightly differently with a slow rise in velocity that you can see on the velocity curve graph above. This actually gave a higher average velocity for the second 10-shot string. I’m reporting the first and slightly lower 10-shot string to remain consistent, and also because it better simulates actual shooting conditions. You’re not going to pop off 10 blanks before you actually start shooting! This gave me an average velocity of 558 fps, a 94 fps gain over the 7.5 inch barrel.

That’s it for today

I had to break Hiveseeker’s report into two parts. The second part will post tomorrow as Part 11, so it will be as seamless as I can make it.

This is a monumental test he has done. Many readers have been asking for this kind of data and have been talking about it. I hope you readers appreciate what he is doing.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

45 thoughts on “Crosman 2400KT CO2 Air Rifle – Part 10”

  1. Hive seeker— I am getting similar results with my Sheridan 2260MB rifle. Does my Sheridan ( made by Crosman ) have the same Crosman 24″ barrel that you are using ? Or does Crosman have a different barrel for pistols ?——-Ed

    • Chris
      Well there you are. I was wondering when you was going to make it back. And don’t know if you been keeping up with the blog. But check out the bb shooting I did over the weekend with my QB79 if you haven’t already. I got some pretty good results.

      • GF1,

        Yup,.. still here. I have been keeping up. Nice mini-shotgun groups. Just taking it easy, still working, none missed. This bug seems to hang around 2-3 weeks after the initial hit from what I am seeing of others at work.

        • Chris
          Yep on the hanging around. My wife still has it.

          And what I learned on the You Tube video’s. Is on the top right corner of the video there is 3 vertical dots you can click on. Once you do that you can click on the Play Back Speed. Then a screen comes up of how slow you want to go.

          If you click on my slow motion video then go to the lowest speed play back setting you can actually see the bb’s leaving the barrel and impacting the can. Then see the spinner behind the can get knocked up as the can falls forward and bounces.

          Since I found that feature from You Tube I have been using it to replay some of my shooting videos. The balloon burst video I did with the balloon in a can with cool aid sprinkled on the top of the balloon is cool to watch in the super slow motion.

          And hope your get better.

    • Gunfun1,

      I wish. I WISH! “Barrel length and accuracy” could be another big test, but this test was fairly extensive as it was and I’m pretty sure the results would not be conclusive. The reason I say that is accuracy of Crosman barrels reportedly varies. In particular, I’ve heard of a lot of variability among their 18 inch barrels. I’ve read few complaints of anyone getting a “bad” barrel, but some Crosman barrels are reported to be pellet-on-pellet accurate. All I can say from the half-dozen or so 2400KTs I’ve accuracy tested is that my Crosman barrels are pretty accurate but that the available Lothar Walther barrels are unequivocally better, especially as you move out to 20 yards or more.

      • HiveSeeker,

        I’d say “fairly extensive” is an understatement. I know from the various testing (read “goofing around”) with my airguns just how much time a delay of 90 seconds between shots eats up. And that’s part of why this sort of data is not that prevalent. That long delay is absolutely necessary for the data to be meaningful and most people won’t spend the time; if your not wired right it will seem boring. Well lucky for us you are wired right and now you are generating data that will be available as long as the WEB exists. Great work and good on ya!

        Do you think the Sheridan 2260MB rifle has the same power valve in it and would you know if there is a LW barrel in that length, or close to it, available for the 2260MB?

        • Halfstep,

          You’re one step — or at least a “halfstep” — ahead of me! I just asked Zimbabweed above for some velocity data on his 2260MB because I’m wondering the same thing. From the specs and from some forum posts I’ve thought it may have the Crosman “power valve”, but the Crosman parts lists show the same valve as the 2240 (part 2250-003). I’m wondering if the MB (metal breech) version PA sells comes with the power valve.

          Sadly, the 14.6″ is the longest Lothar Walther barrel compatible with Crosman CO2 guns that I’m aware of. I was ecstatic when it was announced and ordered another 2400KT with that barrel within days of its availability. FYI I tried to get a part number for that barrel from Crosman and they wouldn’t give it to me, stating that the barrels are in such short supply that they are basically not available for standalone sale right now.

      • Hiveseeker
        I have Crosman barrels that shoot better on a paticular gun than the Lothar Walther barrels on the same gun.

        And I know the testing all takes alot of time. But like how you chose .22 for hunting. Well accuracy is a real important part of hunting.

        Yep I like to know the power the guns making but mostly I want to know how accurate it is. I have had guns that made good power but mostly just sat or I got rid of them because they weren’t the kind of accurate I wanted. As you can tell you see where I’m going.

        • Gunfun1,

          You are right, it helps to be slightly OCD patient when it comes to this rigorous kind of testing.

          And that’s what I’ve heard about the accuracy of the Crosman barrels. On the forums folks ask if the Lothar Walther barrels are worth it. I say yes, and others say their Crosman barrel is just as accurate so save your money! Again, no one seems to get a “bad” Crosman barrel but some folks end up with “super” Crosman barrels! Not me so far.

          And I hear ya on accuracy. A gun is most fun it you can hit what you’re pointing it at. I’m going to steal one of B.B.’s favorite quotes:

          “Only accurate rifles are interesting.” — Col. Townsend Whelen

      • Hiveseeker
        Something else I forgot about that we talked about in the past when you was trying to figure out the valves and power on your guns.

        It was the transfer port orafice size. Did you ever get a chance to see if your guns had different inside diameters? That will play a big effect on velocity.

        Since you mentioned the different valves it would also be nice to know if the transfer port played a part in the different performance.

          • Hiveseeker
            You know what this is almost what I commented today.

            Nice blog. But I think I will just hold off on my comments till I see what Wednesday’s report consists of.

            Now I know that’s what I should of said. 🙂

            But yep as always interested to see what you have to report. And all I can say is for the money the custom shop guns are worth it. Cost wise and accuracy wise. 🙂

  2. Hiveseeker,

    It is too early in the morning for my head to scrape up intelligent sounding words, but thanks for testing and recording the data that most of us would “instinctively” expect (I did manage one big word). It is nice to be able to prove what we are saying.

    Thanks for sharing and be sure to continue to have fun with that morphing thingy.

    • RidgeRunner, more than welcome. A lot of what’s generally been reported is entirely correct, but sometimes going to the extremes can be revealing. How far can we go? We’ll find out — theoretically — tomorrow.

    • Hi Bill Feese,

      You are welcome. I’ve been wanting this data for a few years too, and finally realized I would have to make it myself! There is a lot of information out there in the various modding forums, but scattered about and not always consistent. But what I was able to find helped guide this test.

  3. HS,

    Great report! Thanks for share and all the work involved.
    Now I think that you need to get an aftermarket valve for the 24 inch barrel. Instead of friction, I think the reason for the lower shot count is because the volume of gas needed to push the pellet out needs to be greater because the volume of space before the pellet leaves the barrel is so much greater. Hope that make some kind of sense?

    Nicely done,


  4. Hi Yogi,

    Well, you’re already up to Part 12! That’s actually in progress right now. But I will tell you that the valve would not have made the difference — I’m pretty certain in this case it is barrel friction we are seeing. Note that the drop-off does not occur until the CO2 starts to become depleted at around shot 25. Up to that point, the power curve looks just like all the other barrels.

    However, please do stay tuned and we’ll be talking about aftermarket valves soon!

  5. Great blog HiveSeeker – really enjoying the series!

    I’m going to have to look into these Crosman barrels to see if I can fit one to my Crosman 101. The original barrel has seen a lot of use.


      • Hi B.B.

        It’s a steel barrel and the rifling consists of fine scratches with no real lands visible. There is no damage/or rust pitting in the bore but a 5.52 pellet can be pushed through with very little resistance.

        The plan is to get the rifle resealed and working, finding the golden pellet and shoot groups to see what it will do. Depending on the results I may see about putting on a modern barrel.

        First major snowfall today. Six inches on to ground and more to come – looks like it is here to stay 🙁


    • Hi Vana2,

      I don’t know if the current crop of Crosman CO2 barrels are compatible with a 101, except to say that if any of them are, then all of them are. You can probably Google it and see what turns up from the modding forums.

      • Hi HiveSeeker,

        If/when it come to re-barreling it should be a straight forward matching of diameters (shimming or reaming the supports and breech) and drilling the air transfer port.

        Will cross that bridge when I come to it 🙂


  6. Hello HiveSeeker,

    Great article! Lots of work, great writing, and great graphics. It is very interesting that the data is so consistent.

    My first airgun purchase was the 1322. I worked with it some, but was not satisfied with my accuracy. Now that I’ve had more shooting experience, I’ll pull that sucker back out and give her another try.

    I look forward to tomorrow’s article! And I’m going to go back and read the first nine parts!

    Thanks and best regards,


    • Hi Dennis,

      I have deliberately avoided mentioning the 1322 and 1377 because that opens up a whole big wide arena of discussion! BUT my love affair with the 2400KT began when my 1377 died and I wanted a replacement I wouldn’t have to pump. These guns all share a lot of parts in common, and Crosman just added the 1300KT based on the 1377/1322 to their Custom Shop which opens up a lot of new possibilities. People mod these guns almost as much as the 2240. I loved mine, but the ones you can buy now are even better.

  7. Super job, HS. I fear if you do try to compare accuracy among barrels, you’d be tackling an even bigger test as first I would think you’d have to find which is the most accurate pellet in each barrel! Perhaps you’d find that Crosman Premiers are the answer but this could take a weeks worth of shooting among 5 barrels and only you know how many pellets you’d think of trying in each barrel. By the way, as you purchased it from the Custom Shop, that is a really handsome rifle.

    Fred formerly of the DPRoNJ now in GA

      • B.B. and Fred DPRoNJ,

        Ha, that would surely be “The NeverEnding Story” of the airgun world! Having put a lot of different pellets through a bit of a collection of 2400KTs, I actually have a list of recommended pellets I was going to include in today’s blog. However, it ran so long that I moved that list to what will be Part 12 on modding.

        I’ve found some really good pellets for particular guns from reading others’ experiences and recommendations. Certain guns do tend to like certain pellets, and I’ve been absolutely amazed at how different two different pellets can shoot out of the same gun. Of course, there’s variation within model types too. As Gunfun1 and I were discussing above, some Crosman barrels are super accurate and some are not — it varies. He’s been luckier than I have in that regard. From my experience, the Lothar Walther barrels definitely make a difference.

      • BB

        and pellet seated vs flush. Oh, and pellet seated in different depths.

        But backing away from humor I don’t hear much in recent times about pellet seating improving accuracy in any gun. Velocity yes sometimes. Was it a passing fad?


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