You're asking what is "effective" without defining what you consider effecitve.

M855 will reliably fragment out to about 50 yards and M193 out to about 100 yards.  Using Winchester PP, you'll get expansion out to 300-350 yards or so.  (Note that these are estimates; environmental conditions have an effect on ballistics, so nothing is absolute.)  Other types of bullets will have different performance envelopes and damage profiles.  You can't make accurate generalizations that apply to these different types of ammo.

So, what is "effective"?  In the minds of most experienced folks, "combat effectiveness" means a weapons system that creates enough damage to take the enemy out of the fight.  If your definition is different, so will your answers be.

Standard military FMJ won't damage much tissue if it's moving too slowly to fragment, or if the bullet hits in too thin of an area.  But, *IF* you can hit someone's Central Nervous System [CNS] (i.e., head/spinal column), you will almost certainly take them out of the fight.  But the CNS is a fairly small target.  The spinal cord is an inch wide, and protected by big bones.  The brain is a bigger target, but is armored by a rounded skull.

If you manage to get a head or spinal shot at ranges out to 500m with military FMJ, your shot will be "effective."  If you don't, you may cause a wound that kills your enemy eventually, but one that probably won't prevent them from continuing their assault in the short-term.  In other words, a non-CNS shot with military FMJ beyond fragmentation range is usually NOT "effective" by our definition.

The problem is that weapons manufacturers use "accurate enough to hit a target at x meters" to define "effective."  Under that definition, an M4 is effective to 5-600m.  But they make no mention of damage or wound profiles at those ranges.  This shouldn't surprise you: it's called MARKETING.

In my opinion, the M4 is a specialized, CQB-type weapon.  In that role, it is excellent.  It is NOT a general-purpose rifle, though.  For that, use a 20" rifle.

The whole Black Hawk Down experience should have taught us this.

-Troy

Quoted: but even a .22 hole through the innards would probably get most people to reevaluate their priorities.

Oh, if this were only the case.  Have you read much non-fiction about armed combat?

Unfortunately, it is VERY common for attackers not to even notice that they've been mortally wounded until long after the attack.  Many eventually die, and more are saved in the ER, but you have to either cause DIRECT damage to the CNS, or MASSIVE damage to vital internal organs if you want to RELIABLY stop an attacker.  When YOUR life is on the line, 40% or 60% often is no where near good enough.  You want something that has at least a 90% or better chance of taking someone out of the fight with a center-mass shot.

-Troy

Quoted: Troy, You shouldn't rely on the secondhand information from a warrior, filtered through a journalist with no firearms experience as reference material on the effectiveness, or lack thereof, of military ammunition.

I think you know that I take "journalists" versions of events with many grains of salt.  But I've read lots of other well-documented, historical books, mostly from WWII and later, that talk about people being mortally wounded (on both sides) and continuing to attack.

Also, a great number of medal citations, especially older ones, talk about the person continuing to fight or help others after being wounded.  There's plenty of historical evidence of this happening; certainly not limited to Somalia.

If anything, the events of Oct 3-4, 1993 served to show just what our warriors are made of.  I for one am damn proud of them.

Agree 100%, and in no way am I trying to suggest anything different.  TFR had a hard mission that turned much, much harder, and they did incredibly well under horrible circumstances.  While I have issues with the reasons the leaders sent them there, the soldiers themselves got it done, and did a great job.

If you like, we could start another topic in the Ammunition Forum to explore this further, but I think it wouldn't bring out much new material.

I agree, but I'm always willing to discuss...

-Troy