What is the best defensive round in the following calibers:

.40 S&W
.357 Sig
9mm

The options for .357 Sig are rather limited, but 9mm and .40 have quite a few options out there and I would like to hear opinions.

Thanks

Edited to add:
The 9mm will be from a Glock 19
The .40 & .357Sig will be from a Sig Pro 2340

Answer is:

Depends. Depends on size of the pistol, barrel length of the pistol, what the pistol works most reliably with, etc...

In 9mm I use Speer Gold Dot 124 grain +P rounds in my Berettas and my Walther P99 (Longer barrel) and I use CorBon 115 grain +P ammo in my Sig P239. (Short barrel...) Speer also makes a +P+ Gold Dot in 115 grain if you can find someone who sells em.

When I had a 40 I carried 155 grain Federal Hydra-Shock rounds in it. Very good rounds.

In .45 I carry 230 grain Federal Hydra-Shocks.

In a .38 Spl with a short barrel like my Smith 442, I carry 158 grain lead Semi-Wadcutter hollowpoints loaded to +P velocity.

General rules are these:

1. Choose a bullet appropriate for your barrel length. Jacketed bullets and heavier bullets need velocity to make them expand. Longer barrels = longer velocities. If you are shooting a full sized handgun, heavier bullets are usually OK. (Thus my choice of 124 grain rounds in my Berettas and a 115 grain round in my Sig P239...)

2. Choose a good bullet design. Speer's Gold Dot rounds are very good, and tend to penetrate barriers better. Hornady hollowpoints are good a dumping energy. Federal's Hydra-Shocks dump energy well too.

3. Choose ammo that is reliable!! Above all else, shoot whatever gun/ammo combo you plan to use extensively to make sure it is reliable.  

The test results I saw which were results of police action shootings of real criminals- remember that this is with adrenaline pumping and shot placement may not have been absolutely perfect:

NOTE: .45ACP information was taken from over 200 shootings while the other calibers do not have as much experience to draw from.

40S&W Federal Hydrashok (I think it was 155 grain) 98% one shot stop

45ACP 230grain Federal Hydrashok 97% one shot stops

The 9mm Hydrashoks were around 87% while 9mm ball was a pitiful 47% (87% is more than fine by me as the 9mm guns hold twice as much ammo to begin with)

For comparison only
45ACP Ball 74%one shot stops

Federal Hydra shok ammo holds somthing like the top 5 positions for stopping [KILLING] efficiency so whatever you get rule out the others and get hydrashok ammo

I carry ball ammo as I can't afford to practice with Hydrashok ammo so I will not use it. I know this may sound stupid but I figure if I want it dead I'll pull the trigger twice and then with .45 ball I have a guarantee he won't shoot back.

When I had a .357 sig (it was a Glock 32) I carried 125 grain Speer Gold Dot hollowpoints in it. The .357 sig is a really hot round, so you have more leeway with it than with a 9mm.

Knowing what guns you plan to carry would help with reccomendations...

Your question is very common, I have seen it on different boards on the internet and the one thing that sings from a question like that is what do you shoot and shoot well? I have met Peter Pi when I lived in Wyoming and have seen the factory and their studies on bullet expansion. They are slowly making heads turn with their personal defense ammo. I would recommend their ammo or the Federal Hydra Shock ammo.

The only thing to remember about your choice of weapon and ammo is... When it counts can you hit what your target when/ if the situation ever came to that.

The one well placed shot will kill, even with a .22, never forget that you can't catch up in a shoot out when the winner is the one still alive.  

Right now, the very best performing 9mm you can buy is the 127gr +p+ Win Ranger-T.

It's hard to get a hold of, but multiple studies have shown it to be the most impressive in just about every medium.

www.ammolab.com

Decide what your needs are based on their performance.

Lumpy196, That's an interesting page... According to his tests, it seems that the 9mm Hydrashok's didn't expand at all out of a Glock 17 or 19. I thought the HydraShok was one of the best defense rounds?

Anybody heard anything about Aguila's IQ line of cartriges? (good or bad)

9mm Winchester Ranger 147Gn RA9T

Winchester 175gr. Silvertip 10mm

I want to know how .45 plus P and .45 Super do.

Choose a round that works in your pistol and practice with it.
The most important thing is PLACEMENT, im running 165gr golden sabers in my glock 27 because they expand even through 4 layers of denim.
In my sig 220 im running corbon 165gr hp, real hot and fragment.
No bullet performance matters if you dont hit the target.