What *is* the point of the .223/5.6 in combat?

In addition to the many factors already listed, I would add that the vast majority of firefights take place at 200 yards or less, most much closer than that. 5.56mm ball (M193 and M855) both have DEVASTATING wound ballistics inside 100-150 yards (above 2700 FPS). Energy dump is voodoo science...all that matters is how much tissue is destroyed, and where the shot hits. See the following:

http://www.fen.baynet.de/norbert.arnoldi/army/wound.html
 
The caliber chosen depends on the tactics in use, too. It's all one package. If you want to do fire and movement you need suppressing fire, and if you use suppressing fire you need to have a lot of rounds to shoot, and if you have a lot of rounds you have to carry them. So a lighter round is a big advantage to the whole tactical picture. And 5.56 is good enough at 0-250 yards, where most rifle fire occurs.
 
Though I will show my miserable education...

may I ask this rather dumb question? Well, I'll ask it and hope the snickers are not too loud.

Are the two rounds - .223/5.6 the same - meaning are they interchangeable in any particular .223 or 5.6 rifle? It sounds to me that they are not, but I want to be sure. What, then, makes the difference, if any?

-Andy
 
223/5.56 in combat

It is my understanding the 5.56 NATO is loaded to higher pressure than the 223 and the shoulder angle is slightly different in the two. A semi auto chambered for 5.56 will chmaber the 223 but the reverse is not wise. I have spoken to Winchester Ammo about this and this is their advisement. They specifically point out their USA is 5.56 and not .223.
 
Umm, I hate to put my foot in the door on such a heated arguement, But...

Isn't one advantage of the 5.56 a relatively flat trajectory out to about 500 meters? So, a soldier could deliver fairly accurate fire at 100 meters or 500 meters, without changing sight settings. Pretty important, if you don't know what the visibility is like when you'll be in combat, or when you don't know what range you'll be engaged from...

I'm just thinking of the movie "The Lighthorsemen" - when the Turks opened fire on the advancing Light Horse at 1,000 yds. The Turks slid up their volley sights for the initial volley. As the horsemen advanced at full gallop with sword bayonets drawn, they forgot to drop their sights down as the range changed. So, they were firing well over the advancing soldiers. Human beings tend to forget little details like that under pressure...

I think when the Army switched to the SS109, some of the advantage of the flat trajectory was lost. Heavier, slower bullet=less distance covered horizontally vs. vertically.
 
My recollection is that the key difference is the length and angle of the throat area. M193 rounds (5.56mm) will generally chamber in a SAAMI .223 Rem. dimensioned chamber, but the hard seating of the bullet ogive into the throat will dramatically increase pressure.

Not good at all. Both Ruger and Kimber bolt guns in .223 were used in one test I read about.

Back to the ammo discussion--it all seems to be rather mission-specific. Snipers and vehicle/materiel destroyer missions are generally better served by the 7.62mm. Longer range engagements are better served by the 7.62mm. Light-target firefights and CQB are better served by the 5.56mm.

I'd still like to see a totally new military round with a 6.0 to 6.5mm bore, a case head about the size of the .40 S&W, and a case length shorter than 7.62mm, perhaps as short as the 5.56mm. The extractor rim would be thicker, like the Ruskie 5.45x39 round. Launch a bulet between 90 and 105 grains, with a steel penetrator tip and a nice high ballistic coefficient. Those two factors will make it quite unstable in tissue. Because I like to destroy harder targets, keep the jacket strong enough to NOT fragment in tissue, but have it designed for fairly rapid terminal keyholing (like flat-base 7.62x39s instead of BTs).

One thing that no one has mentioned. If the wind is blowing very hard at all, the 7.62mm has MUCH higher hit probability at 200 yards and beyond.

If your compromises include only 10% of your shots fired at 250 to 500 yards, air support for vehicle disablement and a need for more than 100 rounds per day per soldier, the 5.56 using the newer ammo is the better choice.
 
IIRC, the flatter trajectory held out to only 300 yards. After that, the M193 was slowing down quite a bit, hit like a 9mm, and was blown all over the place by the wind.

The newer bullet tracks the trajectory and wind drift of the 7.62mm ball round. The 7.62mm Match round (173-gr BT) had almost the same trajectory but even less wind drift. Higher BC +only slighty less speed = a bit more trajectory curve inside 300 yards and less curve from 400 to 1,000.
 
Cheapo,

'd still like to see a totally new military round with a 6.0 to 6.5mm bore, a case head about the size of the .40 S&W, and a case length shorter than 7.62mm, perhaps as short as the 5.56mm.
Click to expand...

All you said here is good, but what you describe is basically the 6mm PPC. Make a round with this casing and a higher pressure, 54,000 instead of the normal 45,000 and you would have one monster round, that would have incredible velocity, fit in existing AK magazines, and could be made to fragment, pierce armor, AND destabilize in soft targets...
 
Danger Dave, in my previous post I stayed away from comparing the 5.56 with other cartridges, and offered what I've read as to the military philosophy for going to this cartridge/rifle combination...I still think my post sums up the "why" for battlefield use.

Ironbarr, Byron: The only difference between civilian and military .223/5.56 is the thickness of the brass, and the military stuff--designed for semi-auto/full-auto use--is "small base" (just like military .308, and same reason) so that it will chamber and extract more easily with the weaker mechanism. A bolt action is far more positive in locking into batter, and in extracting the spent case. I have not used a micrometer on new ammo to compare GI stuff with civilian, but it's probably not more than one or two thousandths of an inch difference.

Factory pressures are roughly the same. If you handload, and use a load suitable for civilian brass, the slightly lesser capacity of the military brass can readily lead to unsafe pressures.

While I have not compared the case capacity for the civilian vs. military in the .223, I do know that for the .308 the difference is around three grains weight of powder. Roughly. Same for the .30-'06.

New, out of the box ammo will do just fine in any bolt action, whether or not it's military issue stuff.

Hope this helps, Art
 
First...

I thank all for treating my query with respect - it has been a very long time since I've "rifled" with something larger than a .22 single shot Winchester.

Second, I do appreciate the info and data that's been made available to me. I'll continue to monitor this thread for further input. I do have a question about (to me) the newer hardware - this I will post separately.

Thanks all.

-Andy
 
I reload the 62gr Steel core rounds and I'd like to hear some opinions on the M193 and the SS109 stuff? Does the Military claim the both fragment on impact?
 
SodaPop, one of the criteria for the heavier bullet was that it penetrate a GI helmet at 600 meters. At that distance, it ain't going fast enough to fragment.

Most any .22 centerfire will fragment at close range, except maybe stuff like a .22 Hornet...

Art
 
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