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Ammo for the AR-15. .223 Vs 5.56Nato

13738 Views 25 Replies 11 Participants Last post by  Jeremy
What are the pros and cons of each?

The round actually looks different if you look at them side to side, the 5.56 is sharper and more angular, whereas the .223 is more rounded.

I've heard that the 5.56 has a better probability of splintering when it comes in contact with the target which makes it more lethal. Also, I've head that the 5.56 is flatter and more accurate.


Anyone know any cold hard facts?
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http://www.thegunzone.com/556v223.html
http://www.ammo-oracle.com/body.htm#chamb


If you are looking for accuracy. go with federal Gold Match serria match king .223 rem

if you want stopping power go with honady TAP in .223 rem

if you want cheap go 5.56 nato surplus

if you want 5.56 that is more accurate than cheap surplus use lake city
5.56 is more likely to splinter cause its steel core is hard and brittle, most 223 is lead. 5.56 tends to be hotter but not always anymore. Basically the 5.56 NATO was a re-engineered 223 by FN Herstal in the late 60's and early 70's to make it penetrate better and have more mankilling punch. Before that the US used the old 55gr load vs the later 62 grain. My AR15A1 has teh best twist for the 55gr (1in 12) while most have a 1in8-9 nowadays so the heavier bullt doesnt start tumbling after 1-2 hundred yards.

5.56 brass tends to be thicker and it wont always work in the tighter chamber of a 223 match rifle just to let you know.
5,56 brass is thicker and more straight lined. A nato round can be made in just about any country on any machine that will form casimgs technically it's easier to keep the brass fustionable and withing safe firing specs at the case neck if it's a straight angle rather than a rounded "blown out" shoulder. Inherently a rifle chanbered for 5.56 nato has a bigger chanber to account for the differences in ammo tolerances. Which can cause a problem if you get a bad .223 rem round. The bigger 5.56 chamber doesn't hold a 223 round as tightly and the thinner brass in the 223 can stretch and blow apart . Not a common malfuction but it does happen. Until recent years the 556 was loaded faster. With the thicker brass and different chamber and throat it could be loaded hotter without increasing the pressure to unsafe ranges. While yes the rounds for 556 can splinter that's usuallty the jacket seperating from the steel core but as far as more lethal that a 50/50 There is also the arguement that the 556 was designed to wound rather than kill imediatly for the simple fact that a dead soldier takes only 1 person out of battle while a seriously wounder solder takes 3 out of battle; the guy hit and the 2 guys to carry him out of the engagement zone. You pick decide which makes more sense

If you really want to know I can explain the differences between the 2 in detail for you but it's to much to type in here. They can be very different rounds. To be safe shoot only ammo that matches the gun 556 in 556 and 223 in 223 1 bad casing can really ruin your day.
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from what i have learned in the past month and half... lol...

223 in a chamber for 5.56 is fine.

5.56 in a 223 isnt fine...
Jeremy said:
5,56 brass is thicker and more straight lined. A nato round can be made in just about any country on any machine that will form casimgs technically it's easier to keep the brass fustionable and withing safe firing specs at the case neck if it's a straight angle rather than a rounded "blown out" shoulder. Inherently a rifle chanbered for 5.56 nato has a bigger chanber to account for the differences in ammo tolerances. Which can cause a problem if you get a bad .223 rem round. The bigger 5.56 chamber doesn't hold a 223 round as tightly and the thinner brass in the 223 can stretch and blow apart . Not a common malfuction but it does happen. Until recent years the 556 was loaded faster. With the thicker brass and different chamber and throat it could be loaded hotter without increasing the pressure to unsafe ranges. While yes the rounds for 556 can splinter that's usuallty the jacket seperating from the steel core but as far as more lethal that a 50/50 There is also the arguement that the 556 was designed to wound rather than kill imediatly for the simple fact that a dead soldier takes only 1 person out of battle while a seriously wounder solder takes 3 out of battle; the guy hit and the 2 guys to carry him out of the engagement zone. You pick decide which makes more sense

If you really want to know I can explain the differences between the 2 in detail for you but it's to much to type in here. They can be very different rounds. To be safe shoot only ammo that matches the gun 556 in 556 and 223 in 223 1 bad casing can really ruin your day.
And the same malfunction could happen in a .223 rifle with the same bad round so that kind of negates your point here.
If you are getting an AR, ALWAYS have it chambered in 5.56. I can't think of any damned reason why you wouldn't want it chambered in 5.56. This excludes match grade barrels, some of them are .223 only but i'd try to find a 5.56 one if possible. The NATO round is a higher pressure round, hence the flatter ballistics and the splintering on impact.
I have run both in my AR's from the day I got them, and never had any trouble with neather. I mainly run 223 reloads from Georgia Arms in mine but sometimes run 62 grain Lake City steel core when ripping an old car apart or something is it bad? I have no idea, if it is oh well il buy a new barrel because I have bairly enough to feed all the starveing guns I own.... I shoot about 700-1000 rounds a month of 223/556 in my AR-15s, M4 carbine and Mini-14.
BhamRoadrunner said:
Jeremy said:
5,56 brass is thicker and more straight lined. A nato round can be made in just about any country on any machine that will form casimgs technically it's easier to keep the brass fustionable and withing safe firing specs at the case neck if it's a straight angle rather than a rounded "blown out" shoulder. Inherently a rifle chanbered for 5.56 nato has a bigger chanber to account for the differences in ammo tolerances. Which can cause a problem if you get a bad .223 rem round. The bigger 5.56 chamber doesn't hold a 223 round as tightly and the thinner brass in the 223 can stretch and blow apart . Not a common malfuction but it does happen. Until recent years the 556 was loaded faster. With the thicker brass and different chamber and throat it could be loaded hotter without increasing the pressure to unsafe ranges. While yes the rounds for 556 can splinter that's usuallty the jacket seperating from the steel core but as far as more lethal that a 50/50 There is also the arguement that the 556 was designed to wound rather than kill imediatly for the simple fact that a dead soldier takes only 1 person out of battle while a seriously wounder solder takes 3 out of battle; the guy hit and the 2 guys to carry him out of the engagement zone. You pick decide which makes more sense

If you really want to know I can explain the differences between the 2 in detail for you but it's to much to type in here. They can be very different rounds. To be safe shoot only ammo that matches the gun 556 in 556 and 223 in 223 1 bad casing can really ruin your day.
And the same malfunction could happen in a .223 rifle with the same bad round so that kind of negates your point here.
If you are getting an AR, ALWAYS have it chambered in 5.56. I can't think of any damned reason why you wouldn't want it chambered in 5.56. This excludes match grade barrels, some of them are .223 only but i'd try to find a 5.56 one if possible. The NATO round is a higher pressure round, hence the flatter ballistics and the splintering on impact.
To a point yes the same can happen in a 223 chamber but being smaller the case can't rupture as much, guns are made with this problem in mind, a 223 rupturing in a bigger 556 chamber doesn't vent the pressure the way the gun is designed to. Either bad reloads or cheap 223 bulk ammo made by any1 with a chemistry set cause this problem.
I do agree that for an AR always get 556 chamber. 223 chambered guns (all the major AR makers chamber both) have a REAL big problem with 556 ammo. 556 is loaded to higher pressure than 223 and the throat of a 223 is shorter so firing a quality 556 round like black hills in a 223 raises the pressure at least 15000-20000 psi right off the bat.
I found some of my old military "surplus" ammo. (Don't ask how i got it since i've never bought surplus ammo) I'll post up pics side by side, when you look at them you can instantly see the difference.
Hey... I picked up some well used surplus M-16 mags years ago for 5 bucks a mag and they have been the best mags I have had still using them, other than the Steel british ones that scrape EVERYTHING... God my poor AR-15 lower recevers take a beating from inserting them but you cant see it, But they run flawlessly.
My military "surplus" mags have never given me any problems. I've still got like 6, um, surplus mags still in the plastic bags from the factory.
well.... mine were used but still work great.
Me thinks someone isn't catching the joke here about the "surplus" Ammo and mags :laugh:
I suppose using the old "acquire" joke wouldn't help much, then, would it?
Shad said:
I suppose using the old "acquire" joke wouldn't help much, then, would it?
Do they actually count as military "surplus"? or more like military
"doesn't know they're missing them " mags? lol
Jeremy said:
Shad said:
I suppose using the old "acquire" joke wouldn't help much, then, would it?
Do they actually count as military "surplus"? or more like military
"doesn't know they're missing them " mags? lol
And we have a winner. :D
Jeremy said:
Shad said:
I suppose using the old "acquire" joke wouldn't help much, then, would it?
Do they actually count as military "surplus"? or more like military
"doesn't know they're missing them " mags? lol
Surplus- Sold at stores and gunshows
"Surplus"- Commonly found among those who either are or were in the military. Stuff that convienently "fell out of my pack" on a 27 mile hump.
Especially if they were in a hurry when they issued it to you and never made you fill out a hand reciept. If I don't sign for it, they don't get it back. I've gotten a lot of good shit like that. Like the old school load bearing vests from when we didn't have the new M.O.L.L.E. vests, got 2 of them bastards.
Shad said:
Especially if they were in a hurry when they issued it to you and never made you fill out a hand reciept. If I don't sign for it, they don't get it back. I've gotten a lot of good shit like that. Like the old school load bearing vests from when we didn't have the new M.O.L.L.E. vests, got 2 of them bastards.
Let me know if you got anything ya might be willing part ways with. I could use an old skool LBV. :laugh:
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