I carry pistols chambered in both cartridges mentioned. I am tempted to get rid of my 40 and stick to 9mm just to keep one type of ammunition for this type of pistol.

My wife shoots a 9mm and has no interest in a 40 so the decision will be an easy one when the time comes.

Thanks for all of the input folks. I'm thinking that I will order the Smith & Wesson Shield in 9mm for my wife and a Ruger SR9c for myself.

Ruger makes a good quality product that is made in the USA something that is rare in to today's world.

I don't think you can go wrong with either one, the ruger weighs a bit more if that matters.

Looks like you've figured out the pistols you're getting. I've carried the 9mm and .40 both on duty and off. 40's shoot a little hotter but are still pretty manageable if you practice. Ballistically, you get a little more with a .40 but shot placement is still where it counts. Something else to consider is if your wife is already getting a 9mm, you getting a 9mm also means ammo commonality and maybe one less set of reloading dies, etc. Either way, you won't go wrong. Just make sure you both practice for optimum results. :D

Prisons are full of thugs with 9mm holes in them. The thugs with .45 holes in them are in graveyards!

Here's a link on caliber stopping power.

http://www.chuckhawks.com/handgun_power_chart.htm

9mm for me. Shells are cheaper also.

Bought a 9mm Shield two weeks ago, much better on the recoil from the 40. I have yet to get carry permit/CCW. But I was more comfortable with it than a wide variety of options. Taking the class and test before March.

I respectfully disagree. I believe that ALL handguns are underpowered (at least all handguns that are normally carried and used - i.e. the .454 casul is not underpowered). Something like 80% of people shot with handguns survive the event, across the board, regardless of caliber.

I work in a large trauma hospital in Chicago, and have treated many, many gunshot victims. The vast majority of them were shot with handguns, and the vast majority of them survived, regardless of caliber - I've seen people shot with .22's, .38 special, 9mm, .40, .45 and others. I distinctly remember one gangbanger that was shot in the face at point blank range with a .45 and survived - the bullet did not penetrate the brain.

The majority of them that did not survive were shot through the brain, although occasionally death was due to a bullet hitting the heart or a major artery.

The point of a handgun for self-defense is to incapacitate the bad guy, or make him hurt badly enough that he stops trying to hurt you. When you look at it this way, a larger caliber is generally better than a smaller one - greater chance to inflict damage. But the difference in damage between say a 9mm and a .45 is not all that big.

If you want to stop someone in their tracks/drop them dead with a handgun, you generally need to hit the brain, heart or spinal cord. Otherwise, use a shotgun or rifle - either one is much more devastating than a handgun, regardless of the caliber.

Because of the lack of power in a handgun, shot placement is very important, so choosing a handgun/caliber that you can shoot well with is more important IMO than just getting the biggest caliber possible. Personally, I would choose the largest caliber that you can shoot accurately and handle well, but that also allows for the largest magazine capacity possible so you can increase your chances of hitting/incapacitating the bad guy.

Another reason why a lot of thugs with gunshot wounds survive, is that for some reason gangbangers use FMJ bullets the vast majority of the time IME. I'm not sure why - maybe cheaper and easier to get? FMJ bullets tend to zip through the target with less tissue damage than a hollowpoint.