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

by Steve Johnson

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

I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!

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• Ian on Dec 13, 2011

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 on Dec 13, 2011

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/ca...

• Witt Sullivan on Dec 13, 2011

@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." :)