I recall somewhere there was an Army study that put the fatal projectile energy at around 70 joules for a round placed in the head or torso.
You have to keep in mind the distinction between stopping someone and killing someone. The measly .22 rimfire, mostly used for hunting rabbits, squirrels, and tin-cans, has killed many people. It has a tendency to ricochet off bones, creating long wound tracks. Someone shot with a .22 may appear unaffected, only to die some time later from internal bleeding and organ damage.
I misspoke on this one… I can’t find a good reference but I keep finding bits that define a “hazardous fragment” as one having an energy of 79 joules. Sharpened projectiles can do more damage at lower energies.
I’m not sure if they’re quite the same, but the Canadian C7, which is similar to the M-16 has a max effective range of 300m.
Cite for the similarity part: http://world.guns.ru/assault/as44-e.htm
Damn, can’t find a cite for the 300m part, but I know that off the top of my head. But that’s unscoped. I’m not sure if the max effective range increases with the scope on it.
Anyway for a unscoped C7/M16 the max effective range is 300m, if that helps any. Notice in that site the difference in fully automatic and the three round burst. That would be handy if your going for that type of accuracy in your game as well.
Saying .22 caliber is about as meaningful as saying “car with a four cylinder engine.” Is it a Yugo or is it a formula one race car? .22s range from CB caps which may be marginally powerful enought to puncture a body to high velocity varminting cartridges that are far more powerful than the .223 Rem/5.56mm NATO.
Part of the reason of the destruciveness of the 5.56mm cartridge is that the bullet tends to break in half when it strikes the target at the bullet’s cannelure, an indented groove around the midsedction of the bullet where the cartdige case can be more securely crimped.
And remember that guns don’t kill people, people kill people.
Or actually, guns don’t kill people, bullets kill people.
Well, technically bullets don’t kill people, holes blown in people kills people.
Since this is a game and you are the GM, I have a simple suggestion: let guns be as lethal as you want them to be.
Or, you could describe the effects of each arrow or bullet. “You feel things inside your body touch, which should not be.” or “The arrow has just serverd two of yoour tendosn, and you are having a problem using that arm, roll (blank) against dexterity.”
Christ. Ignore all the speculation and hypothesizing here. This is GQ after all.
The study you’re looking for was published by the CDC back in 2001 and may be found here:
http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5002a1.htm
A previous and related study by the CDC published in 1999 may be found here:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4845a1.htm
You’ll want to concentrate on the “assault/legal intervention” gunshot wound classification. The other two “unintentional” & “self-inflicted intentional” aren’t applicable.
If by “go down,” you mean “die,” as you seem to, no. Not by a factor of greater than three. From the 2001 CDC report linked: “A majority of firearm-related injuries for persons aged 15–44 years were caused by interpersonal violence (Figure 5). For persons in this age group, for every firearm-related homicide, 3–4 persons with nonfatal firearm-related injuries were treated . . .” And from the 1999 CDC report linked: “. . . an estimated 64,207 persons sustained nonfatal firearm-related injuries and were treated in U.S. hospital emergency departments (EDs); approximately 40% required inpatient hospital care.” Meaning that 60% of non-fatal GSW are treated in the emergency room and the person is immediately released.
Global Security.org list the maximum effective range of the M16A2 at 550 meters. And I know the US Marines train on 500 meter targets. Maybe the 300 meters is just for Canadians? 
Not so- or if so, they are remarkably inefficient at it. I’d guess that less than 1% of all handguns have actually killed “folks”. True, a good number of handguns are designed with “self-defence” in mind, which certainly includes the possibilty of "Killin’ folks. ". But by no means all- many handguns are designed for hunting, and many more for target shooting- some of these would be rather poor at “Killin’ folks”. And of course you should know that tobacco kills 10 times as many “folks” a year than guns do.
Gun lethality depends on many many factors- caliber, muzzle velocity, weight of bullet, design of bullet, where the wound is, how tough you are, and even pure dumb luck. I think Cole Younger rode off after getting more than a dozen wounds in the Nrothfield raid. Some dudes will take a small flesh wound, and drop to the ground- either in shock or screaming in pain. Others will take wounds that should be lethal, but keep on fighting. Triskadecamus, matt, and** UncleBeer** have made good and valuable posts, amoung others.
When I went through marksmanship training in the U.S. Army, the farthest targets on the range were 300 meters. I think the Marines are just showing off :).
Effective range has little to do with lethal range. It is more a function of the ability of a weapon to perform its intended function at long range. Hitting individual targets at 1000 meters with a M14 rifle is nearly impossible. Wreaking havoc on a group of soldiers at that range with a M240 machine gun is a piece of cake. Both weapons use the exact same cartridge and achieve nearly identical ballistic effects. The effect of distance on lethality is insignificant in determining effective range. Sighting and employment methods are the main factors.
Marine and Army qualification methods are as different as night and day. The Army uses “surprise” popup targets that appear in a pseudo-random order. Marines shoot at large static bullseye targets on a Known Distance range. Apples and oranges, IMHO.
A couple of real life cases:
- I was shot in the upper thigh with a .22 LP, hurt but no lasting damage.
- In the movie 'Heat" the bouncer at the illegal bar (in real life) got shot in the calf with a handgun a week before the scene was shot. He was on crutches but acted.
- A friend of mine was shot in the arm in the army in Korea and died.
There seems to be too many circumstances to make a general statement.
Forgive me, I was not clear. I mean ‘lose interest in continuing the fight.’ As I said, some animals, like people seem to go to ground when shot. I suspect at least part of the reason is psychological.