I just bought my wife a Walther PPS in 9mm that turned out to be about the same size and even easier to pocket carry than the J-frame Smith I have been carrying for years when I didn't want to dress around "my real guns". Have pretty much decided I am going to get another for myself for that purpose. My first instinct was to get a .40 S&W because, if nothing else "Why not?", but there could be an issue with that gun's size and controlling that round. I am a big guy, and shoot alot, so don't think adjusting to it will be hard (especially after having that .38 bounce around in my hand all this time), but if the bullet loses alot of energy in the shorter barrel it may not be worth doing. I know the 9mm is a super-sweet shooter in that gun, if there isn't a tangible terminal ballistic difference, why take a chance on having to fight the gun? Please allow me to set a few ground rules for this thread... 1) This is not a thread to debate which is better; a 9mm, .40 S&W, .45 ACP, .338 Lapua... I don't care. I simply am having trouble finding good data to compare these two calibers in short barreled weapons. 2) This is not a thread to debate on what and if you should pocket carry. Thanks for your help.