Kahr 9mm vs. .40 S&W vs. .45 ACP Recoil Comparison

Andrew shot high speed video to compare the relative recoil of the Kahr CW9, CW40 and CW45 pistols. The results are what I expected, but it is always interesting to see recoil compared scientifically.

For what its worth, I much prefer shooting the 9mm Kahrs.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Lance

    No brainier .45 is bigger but .40 S&W has higher pressure and a snappier recoil than ACP ever did.

    • Sian

      there’s no surprise there, between the three, the 40 has the most muzzle energy, and that translates directly into recoil and .45 slides tend to be heavier anyway.

  • 18D

    I agree with Lance (for the first time) on this one. There is some kind of urban myth that the .45 has really bad recoil, and its just not true. Of course it depends on the weapon and load, but with all other things equal, the .45 has a pretty manageable recoil impulse. The .40 on the other hand has some of the worst recoil out of the popular duty cartridges.

  • RickH

    Interesting. But wasn’t this done years ago with some type of Ransom rest? It took the human element out of it completely.

  • Ian

    Calling this scientific is a bit of a stretch. They could have at least loaded the 9mm to 1050 fps to normalize the energy across all three calibers. Regardless, the use of a person (or even a ransom rest) invalidates any findings due to lack of repeatability.

    Want to make it scientific? Get some strings (or better, a load cell) and a remote fire mechanism.

  • Witt Sullivan

    Easy to measure. Mount a gun vise on a sliding mount and attach a scale(trigger pull scale or digital fish scale?) to the trigger guard so it measures the recoil energy straight back. If you’re measuring recoil energy, muzzle rise is unimportant.

    You can also use this site to calculate the force, as long as you know how much powder is in the round. http://www.handloads.com/calc/recoil.asp

    • Witt Sullivan

      I just plugged in some numbers based on the highest max loads you can load in all three based on Hodgdon’s Reloading Data Center using the recoil calculator. If the program is correct, 9mm(147 grain bullet) has 6.4 ft. lbs of free recoil energy, .40(200 gr. bullet) has 11.28 ft. lbs, .45 ACP(230 gr. bullet) has 11.87 ft. lbs. The pistols should travel rearward at 19.30 fps,24.94 fps, and 23.74 fps, the .40 has higher rearward velocity in that load. The recoil impulse for 9mm is .66 lbs sec, .40 is .91 lbs sec, and .45 is .45 lbs sec.

      I may have overlooked a heavier load, but I think those figures are more accurate than the “scientific” test that was performed.

      “T-t-t-t-too much time on my hands.” 🙂