[heckler]

The key is to transmit as much energy as possible from the bullet to the target. In theory you could push a .22 fast enough to carry more enery than a .380. But the cross section of the bullet is so small that it cant transmit its energy to the target rapidly and "shock" the target.

Velocity + mass + a good quality hollow point bullet that will expand rapidly and retain its mass are the key to "stopping power".

[The Coopster]

In theory you could push a .22 fast enough to carry more energy than a .380...

That's right, you can. In fact, they refer to it as the 5.56 NATO round (or .223). It's in the M16/AR15.

And it packs A HELL of a lot more punch than the .380.

[xm177e2]

In theory you could push a .22 fast enough to carry more enery than a .380.

Such a thing exists, in handgun form. The FN Five-seveN does this.

FN 5.7x28mm ball:	31gr	2,133fps	309ft/lbs*
Winchester .380ACP silvertip hollowpoint:	85gr	1000fps	189 ft/lbs

Sources: FN, Winchester Ammunition, * calculated by arnieairsoft program