Alot of guys *and gals* love the .40, im personally a 9mm fan. If you loved to shoot the .40, i'd say go with makes you happy

There's no such thing as over kill when you shoot a perp. If I ever have to shoot one you can bet your boots I mean to give him a dirt over coat. The 9mm vs .40cal is a personal choice. I have never shot the 9mm so I would take the .40cal because I shoot it about twice a month. Good luck.

why do you think it is overkill ?

are you thinking about energy or velocity?

VELOCITY
your statement could imply you are thinking of velocity
There seems to be two schools of thought -

1 - E = mass * velocity * velocity
go up in velocity and you get more energy (e.g. 9mm and 40 cal)

2- high velocity could go thru the bad guy and other objects and hurt someone else - these people usually believe in a big heavy bullet going slower so that when it hits an object it deposites all of its energy in what it hits (e.g. 230 grain 45 or 255 grain 45LC, 44 special, etc) - this group usually relies on topics of Relative Stopping Power (RSP) equations and the experiments conducted in the early 1900's. You did state "stopping Power" thus if you search on this topic (RSP) you will find that the 45acp is higher than the 40. Do you think that the 45 has been overkill for almost 100 years?
just kidding...

I would suggest, buy the gun that feels good in your hand and you are comfortable with.
enough of this theoretical stuff - lets go to the range !!

I don't think they had JHP's like we have today - technology has changed

ENERGY
You can get a 9 and a 40 and a 45 that all have the same equivalent amount of energy (OK- almost equuivalent but with handloading you could)

my point is - if you think it is overkill then you could go to a different box of ammo

Thanks for the posts guys. After doing some research, I may actually end up going with a 9mm, for the simple fact that it may be an 'easier' starting cal, faster recovery on double-taps, etc. I may just want to focus on shot placement initially (with the 9mm as the CCW), while saving the .40 for strickly a home defense option.

Opinions?

My opinion, if you shoot alot 9mm is one of the cheapest to practice with, and recoil is a bit easier on the hand. The most important of which for me is the cheaper ammo part since I like to shoot alot and don't have tons of money . I'll stick with a shotgun for home defense and use my glock 19 or 26 for concealing.

I carry a full-size.40. I like the round. That being said, I'm toying with the idea of getting a sub-compact CCW gun and it will be in 9mm. Cheaper ammo and less recoil, especially with the sub-compact, being the two main factors.

A lot of people today get hung up on "stopping" power. Sure, if you shoot ONE time, it's probably best to have the bigger caliber, but in a defensive situation, are you honestly going to fire just one shot and wait to see if the BG is down? Probably not. I know I'd probably empty half the mag. Someone is not going to get up if they're hit 5 or 6 times with good, defensive, 9mm ammo. Especially if your shot placement is good.

Best defensive weapon?

1) 12 Gauge Shotgun w/ buckshot, hands down.
2) Any gun over .38/9mm that you feel confident shooting accurately.

My "drawer gun" (and cold weather carry) is a high capacity .45. (XD45)
My concealed gun is a .40. (Kahr PM40)

If the first shot takes out a major organ, it really doesn't matter.

My future purchases...
Small frame/carry gun? 9mm (XD Subcompact)
Large frame gun? .45 (Springfield Long Slide 1911-A1)

Only to standardize ammo. My G/F loves 9mm. I love .45. I'm dumping the .40. Not because it's bad, but because I only need 2 versions of ammo around!

Jeff

The 9mm is perfectly adequate for defense with good modern hollow points. It's easier to control than .40, especially in compact pistols, and is less expensive to shoot.

Don't get too wrapped up in selecting defensive hardware. The particular gun and caliber you choose is practically irrelevant compared to your mindset, marksmanship, gunhandling skill, and tactics. A trained, skilled fighter will prevail no matter which caliber he's shooting. One millimeter of bullet diameter barely enters the equation.

my carry weapon is the sig p239, i chose 9mm because with this gun i am a better shot with 9mm, and there is less recoil.

I used to own a 239 in .40/257 but sold it. I've got a 9 mil now and I think that's a good caliber for that gun. Too much muzzle flip in the .40. I've got a Glock 23, also a compact, but it isn't as hard to control as the Sig. Some say that Glock has a lower bore axis, therefore easier to handle.

For the 239, I'd go with the 9.