moot1337

The thing is, if you're getting a handgun for self defense in a place where a shotgun or rifle would be available, you're already putting yourself at a disadvantage. With low velocity weapons like pistols/shotguns, the temporary and permanent cavities are scantly larger than the expanded diameter of the projectile, which means that it takes a direct hit to the vitals or CNS of the target for neutralization. Shotguns solve the problem with multiple projectiles, but pistols are a whole different animal, with shot placement being the all-important factor. That said, penetration is the next most important, followed closely by expansion - being able to reach the vitals (12-18" of penetration in flesh) and gaining a larger chance of hitting them with a grazing shot.

If you plan on getting a handgun and not loading it up with a specific self-defense ammunition, there really isn't any point - you'd be much better served by any of your shotguns. When your life's on the line, why bother using anything but what's the most likely to neutralize the threat quickly and efficiently? SD ammunition is tailored to be the best stuff to use in a SD situation, even using low-flash powders to minimize the blinding of the muzzle flash in the darkness. This is not to mention that there have been a world of advances in jacketed hollowpoint bullet designs in the last 10-20 years, lessening the performance disparity between 9mm and 40/45/357. Check it out.

In summary, get something you can enjoy and afford practicing with. Nothing matters more than where you put those shots under pressure, and the ability to operate your weapon under the same. If you get an auto, practice clearing jams and malfunctions. Practice a ton with cheap FMJ ammo, then put enough SD ammo through your gun to ensure reliability. And don't bother loading up with anything other than SD ammo when your life may depend upon it.

Best,
m00t

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And that, my liege, is how we know the Earth to be
banana-shaped.
This new learning amazes me, Sir Bedevere. Explain again
how sheeps' bladders may be employed to prevent earthquakes.
Oh, certainly, sir.