The .40 S&W cartridge is the most popular caliber in law enforcement use today. For you younger officers, the .40 has always been around. For some of us older folks, we actually remember when Winchester and Smith & Wesson introduced the cartridge, and all of the debates on its usefulness for police work. The widespread adoption of the cartridge was not a sure thing, and there were many doubters.
This 40 caliber demonstration video was produced by the Federal Law Enforcement Training Center. It shows the cartridge’s effectiveness in ballistic gelatin and how well it penetrates barriers. The video was made in 1998.
Personally, I believe the .40 S&W is an effective cartridge, and I know our agency has had excellent results with the Speer 155 grain Gold Dot. However, I don’t know if the .40 S&W is significantly better at stopping attackers than the 9mm as suggested in the video.
I carry a gun on duty to protect my life, and a gun off-duty to protect me AND my family. The higher stakes (for me) is off-duty when my family’s lives may depend on my decisions. Off duty, I carry a 9mm and feel perfectly comfortable with that decision. As always, your mileage may vary.