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9mm or .40 S&W: The Debate Rages On | U.S. PATRIOT NEWS & REVIEWS

9mm or .40 S&W: The Debate Rages On

The debate concerning what handgun caliber is “best” has been raging since the first patch and ball were pushed home with a ram rod. Although the argument never seems to go away, it had seemed to decrease in recent years due largely to the wide spread acceptance of the .40 S&W by law enforcement agencies nationwide. But the debate has since resurged and is once again going strong.


The 9mm was first invented by the Germans in the early 1900s and was quickly adopted by the German Navy and soon thereafter their Army counterparts. Although widely considered a reliable round, the 9mm was overshadowed by the .45 cal for US forces, which considered the larger round to have greater knockdown power. However, with the increased availability of handguns chambered in 9mm and a lack of confidence in the traditional .38 cal revolver, the German’s pride was granted a new life in the 1980s. For much of the next two decades law enforcement agencies worldwide not only adopted the 9mm as a standard sidearm but rarely missed an opportunity to sing its praises.

.40 S&W

As the name implies, the .40 S&W was invented by Smith & Wesson and Winchester in the early 1990s. Unlike other handgun cartridges of the time, the .40 S&W was designed from the ground up as a law enforcement round meant to address concerns over penetration, stopping power and recoil. By the end of the decade it had gained increasing popularity and numerous firearms manufacturers retooled the lighter 9mm models to accept the beefier .40 S&W. Once again there was a power shift and before long departments nationwide began trading their 9mms for the new kid on the block. Today the .40 S&W is widely considered the most popular police caliber in North America, although US military forces and many foreign departments continue to favor the 9mm.

New Debate

9mm 40swRecent advances in firearms and ammunition development have caused many to reconsider the 9mm, a debate which has been furthered by a recent announcement by the FBI that it is considering a switch of their own. Of course every debate has two sides and those faithful to the .40 S&W point to a similar announcement by the US Army that it is studying the possibility of dumping the long used 9mm for new sidearms chambered in .40 S&W. But the question remains “Which is better?”

9mm enthusiasts point to its lighter recoil, better target acquisition on follow up shots, increased capacity and accuracy as reasons to retain (or return to ) the older brother. Those in favor of the .40 S&W counter these arguments by stating the recoil is slightly stronger but manageable, target acquisition and capacity is not as important when the first shot works better, and that accuracy is a matter of shooting fundamentals more than caliber. In reality both camps are right, and wrong, in their attempts to quantify what is really a matter of personal choice.

That’s right, regardless of what side of the argument you find yourself on, it really comes down to a matter of personal choice. Yes, a growing number of departments have claimed a need to return to 9mm after experiencing an increased number of frame and slide failures in their .40 S&W models. However, chances are most of those .40s were actually 9mm models that had simply been re-chambered to accept the larger round. Models designed for the .40 S&W usually include a thicker slide and frame and rarely experience the same failures. Likewise, modern .40 S&W models are also available with double stack magazines which allow for increased capacity. On the other hand, whether it is a matter of reduced recoil or mental preparation, many shooters do tend to perform at least slightly better with the 9mm. When shooters are able to deliver well placed shots, stopping power becomes less an issue of size and more about damage to the target. Personally, I have witnessed both rounds perform admirably and have also seen officers using both calibers empty a magazine and still fail to stop a determined threat.

So, like I said, it is a matter of personal choice. The best caliber for you is the one that allows to the get rounds on target with accuracy AND provides you with the confidence that it will work for you.

Disclaimer: The content in this article is the opinion of the writer and does not necessarily reflect the policies or opinions of US Patriot Tactical.

Tom Burrell

Tom enlisted in the US Marine Corps Reserves in 1987. Following service in Desert Storm, he transitioned to active duty with the US Coast Guard. In 1997 he left the USCG to pursue a position in conservation & maritime law enforcement. Tom is currently a Captain and he oversees several programs, including his agency investigation unit. He is also a training instructor in several areas including firearms, defensive tactics and first aid/CPR. In 2006 Tom received his Associate’s Degree in Criminal Justice from Harrisburg Area Community College and in 2010 a Bachelor’s Degree from Penn State University.
Tom Burrell

5 thoughts on “9mm or .40 S&W: The Debate Rages On

  1. I carry both the 9mm and the .45ACP. I have always seen the .40S&W as a solution looking for a problem to solve. With all the new bullets we have for the 9mm, .40S&W and .45ACP any of them will work if put in the right place. So, I will stick with the 9mm and the .45ACP. Just my personal choice. In the end, use the caliber you can shoot the best and make all your shots count.

    1. Great way of saying it. I’d only add the 10mm round to that collection of fine rounds since that’s what the .40 was intended to solve. The .40 probably caused more issues than it has mended. All that ingenuity and countless economic power could have been used to improve on the way we use the traditional and fine handgun calibers.

  2. I personally like the 357 sig better than either the 40 or 9mm
    the 357 has more velocity and ft ibs of energy than either the 9mm
    or the 40 and less recoil than the 40 or 45 its carried by the Texas DPS
    and Secret Service.

  3. Our organization traded our Glock .40 in for new Glock 9mm the Fall of 2014. Shortly thereafter our deputies were involved in a shooting where the armed suspect was fatally shot. Out of a total of five shots fired two were “hits”, therefore the benefit of more rounds available played out in a positive manner in this shooting. They either carry 52 or 69 rounds depending on if they carry 2 or 3 extra magazines. Most of us agreed on the switch after researching and reading about the modern available 9mm ammo. So far we are happy with the switch.

  4. My agency carries the Glock 37 45 GAP, but off duty I carry the Glock 23 .40 loaded with Ranger T-series 165 grain, a round that has devastating stopping power. With an extended magazine I’m able to carry 15+1, same as the model 19 9MM. I own a Sig-226 that I bought in 1989 but have not carried it in years, and I see no need to. Although there have been improvements in 9MM loads, I see no reason to ever carry a 9MM again off duty, the .40 has superior stopping power with a proven track record, quality, not quantity is my motto.

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