Here at K2 we’re big fans of the venerable 9mm, it’s a proven round used by the majority of militaries and police around the world. Since its introduced in 1902 much has changed in more than 100 years for the 9mm Luger, now known by it’s NATO designation 9x19mm, and today it’s better than ever. With modern expanding ammunition the 9mm gives you roughly equal ballistic performance to larger calibers like the .40 S&W and .45ACP. The 9mm has less blast and recoil which means your back on target faster; more magazine capacity means more time in the fight.
Paul Gomez over at Gomez Training International pretty much sums up our feelings on the subject. Check out his article “Wound Ballistics 101" on http://gomez-training.com/articles/1-wound-ballistics-101/ and the short video on youtube before you decide on your next pistol.http://www.youtube.com/embed/2dA36NYLqns?rel=0
These test charts are provided by Winchester to compare their various loadings. Notice how similar expansion and penetration are with the big three calibers through various barriers.
Ultimately you should carry what you’re comfortable with, but don’t let internet hype dictate your choice before you read up on the facts for yourself.