This is a very interesting thread. Let me say first that I'm not big on "assault" type rifles. The closest I come is a couple of Yugo SKS's that I've glass bedded (that shoot quite well!) and my trusty ol' Garand.
In my opinion, there are a couple of issues here that should be addressed.
First is cartridge. I've never shot anyone in my life, but I have hunted for over 30 years and learned that, simply stated, bigger bullets = bigger holes = more internal damage = better killing potential. I have on occassion used .222/.223 for deer, but I only trust them at close ranges, (< 100 yds.) and only if used carefully with high quality hunting bullets. I think this is a very broad concensus. So, if a cartridge can't be trusted to cleanly kill an animal that is roughly the same size as a human being, why on earth would a person want to trust it to kill someone (or something) that bites or shoots back?!?!? Here's an interesting bit on that subject:
The Last "Big Lie" of Vietnam Kills U. S. Soldiers in Iraq
Second is what many have already mentioned: sights/sight system. In my opinion based on my experience from hunting, shooting on the range here at my house, and competing in High Power matches, iron sights are practical to about 200 yds. under most field conditions AND that assumes good lighting. I know, the military shoots out to 600 yds. with iron sights, but this is done in broad daylight, at known ranges firing at large, black targets. My father was in the Army in the 50's and told me they fired their Garands out to 600 yds., but the bullseye was (if memory serves)
3 FEET in diameter. The NRA High Power 500 yard target uses a 24" bull. I've found that most reasonable quality any scope is better than iron sights.
Having said that, my "do all" rifle is Scout Rifle based on a Mauser action and chambered for the 308. I don't shoot 3-gun matches or any such thing, but I am immensely comfortable with and confident in this rifle. It has a Burris 2.75X forward mounted scope and a Redfield receiver sight as backup. I have fired it out to 350 yds. and the little scope works fine for everyday use.
That is why my vote 686+ would be for an M-14 with a Scout type scope set up. The 308 cartridge provides plenty of power and with the forward mounted scope, you pretty much have the best of both worlds; a sighting system that allows use with both eyes open for close range and reasonably easy use at longer ranges. If something goes awry with the scope, take it off and you're still in business.
Having said all that, I probably think differently than most. It seems most people think in terms of urban combat. I cannot imagine, in an "Excrement Contacting the Ventilation Device" situation being ANYWHERE that remotely resembles an urban setting. I rather imagine being as far away from masses of people as possible. That in itself strongly influences the type rifle I prefer.
My 2¢.....
35W
P.S.- What the hell is "overkill" in terms of combat cartridges? Is this in reference to a cartridge that will kill a bad guy "too dead"?
