Found this from a FBI report on Handguns.

The often referred to "knock-down power" implies the ability of a bullet to move its target. This is nothing more then momentum of the bullet. It is the transfer of momentum that will cause a target to move in the response to the blow received. "Isaac Newton proved this to be the case mathematically in the 17th Century, and Benjamin Robins verified it experimentally through the invention and use of the ballistic pendulum to determine the muzzle velocity by measurement of the pendulum motion."

Goddard amply proves the fallacy of "Knock-down power" by calculating the heights (and resultant velocity) from which a one pound weight and a ten pound weight must be dropped to equal the momentum of 9mm and .45 ACP projectiles at muzzle velocities, respectively. The Results are revealing. In order to equal the impact of a 9mm bullet at its muzzle velocity, a one pound weight must be dropped from a height of 5.96 feet, achieving a velocity of 19.6 fps. To equal the impact of a .45 ACP bullet, the one pound weight needs a velocity of 27.1 fps and must be dropped from a height of 11.4 feet. A ten pound weight equals the impact of a 9mm bullet when dropped from a height of 0.72 inches ( velocity attained is 1.96 fps), and equals the impact of a .45 when dropped from 1.37 inches (achieving a velocity of 2.71 fps).

A bullet simply cannot knock a man down, if it had the energy to do so, then equal energy would be applied against the shooter and he too would be knocked down. This is simple physics, and has been known for hundreds of years. The amount of energy deposited in the body by a bullet is approximately equivalent to the being hit with a baseball. Tissue damage is the only physical link to incapacitation within the desired time frame i.e., instantaneously.

This should settle issues of "knock-down power" at this point is personal preference and ammo loadouts.

Just saying if I'm gonna store cash, it will be in Nickels, the melt value in raw metal is worth the same as the monitory value.. best of both worlds..

you might have to bury it tho

1946 - 2010 Jefferson Nickel Value (United States)
U.S. MINT SPECIFICATIONS
Denomination:$0.05
Obverse Image:Thomas Jefferson, 3rd President of the United States and author of the Declaration of Independence.
Reverse Image:1946-2004, 2006-2007: Monticello, Jefferson's mountaintop home in Virgina.
2005: Westward Journey Series including "American Bison" and "Ocean in view! O! The joy!".
Metal Composition:75% copper, 25% nickel
Total Weight:5.00 grams
Comments:The 1938 through 1942 D versions of the nickel are also made of the same composition, but generally are sold for a premium over their melt value due to rarity.

Using the latest metal prices and the specifications above, these are the numbers required to calculate melt value:

$3.0044 =copper price / pound on Jun 24, 2010.
.75 =copper %
$8.8216 =nickel price / pound on Jun 24, 2010.
.25 =nickel %
5.00 =total weight in grams
.00220462262 =pound/gram conversion factor (see note directly below)

The NYMEX uses pounds to price these metals, that means we need to multiply the metal price by .00220462262 to make the conversion to grams.

1. Calculate 75% copper value :

(3.0044 × .00220462262 × 5.00 × .75) = $0.0248381

2. Calculate 25% nickel value :

(8.8216 × .00220462262 × 5.00 × .25) = $0.0243101

3. Add the two together :

$0.0248381 + $0.0243101 = $0.0491482

Just wanted to chime in on this one...

9mm
The energy of this cartridge is capable of imparting remote wounding effects known as hydrostatic shock in human-sized living targets. The existence of this phenomenon was debated in the 1980s and early 1990s. However, recent publication of human autopsy results has demonstrated brain hemorrhaging from fatal hits to the chest with 9mm bullets.

45 APC
The wounding potential of bullets is often characterized in terms of a bullet's expanded diameter, penetration depth, and energy. Bullet energy for .45 ACP loads varies from roughly 350 to 500 ft·lbf (470 to 680 J). It has been shown that bullets transferring over 500 ft·lbf (680 J) of energy in 12 inches of penetration can produce remote wounding effects sometimes called hydrostatic shock

Taken from wikipedia

Both rounds will do the same thing if you suck less @ shooting, hit what you need to hit the first time..

The main point would be what weapon system do you like, all weapons have a different feel to a different user, I prefer my Ruger SR9 over the G17, the grip feels better so I'm more apt to carry it. And along those lines I can shoot my G17 all day over my G21 due to the recoil, the G17 9mm is easier to handle on the wrist, my G21 .45 is a beast.. However the 1911 has enough weight to make the 45 manageable.. Then again you get into firepower loadouts, my SR9 will carry 17+1 stock, the 1911 I have is a single stack 7+1... you tell me, I would like the extra rounds on hand IMO.

Also you have to think about parts and supply's if your getting into this. the 9mm is a newer round but readily available in mass.

The 45 is a older round has been around for years, so also in good supply..

the .40 S+W is pretty new and anybody who has been shooting knows, the weapon system maybe great but if you can't find ammo its a really cool paper weight. Last election the "scare" when though the public and ammo was cleaned out.. for everything and if you could find it you paid for it...

So it goes down to personal preference, if you like the weapon you have you will get the ammo it dictates. However both will do the same type of dmg listed above.

I would suggest starting the thread about AK-47 vs the AR-15... that might get a few comments.

and also, remember just cause its from or in the military doesn't mean its good, just that it's made by the lowest bidder.