.223/5.56 confusion

[NV_ARCH3R]

I've got an AR platform chambered in .223. I've been told, 1) don't shoot 5.56 in it because 5.56 is loaded to higher pressures and it's unsafe. 2) no worries go ahead and shoot no problems. Lots of knowledge and experience here. What say you??

 

[VikingsGuy]

Only .223 Rem in a .223 barrel - 5.56 ammo has higher pressure specs and shorter throat of .223 increases pressure spikes.
5.56 NATO OR .223 Rem in a 5.56 NATO barrel (but with a little less precision for the .223 due to longer throat)
5.56 NATO OR .223 Rem in .223 Wylde barrel with improved precision and pressure profile for both cartridges.

 

[Doublecluck]

Cant shoot 5.56, pressure too high man, you will die.. donate any you have to me and I will safely dispose of it.

 

[RaiderRich]

Only .223 Rem in a .223 barrel - 5.56 ammo has higher pressure specs and shorter throat of .223 increases pressure spikes.
5.56 NATO OR .223 Rem in a 5.56 NATO barrel (but with a little less precision for the .223 due to longer throat)
5.56 NATO OR .223 Rem in .223 Wylde barrel with improved precision and pressure profile for both cartridges.

This! Anyone telling you, you can shoot 5.56 NATO in a .223 Remington does not know what they are talking about. Now if your AR is chambered in .223 Wylde, you can shoot 5.56 NATO in that. Your OP did not state what flavor of .223. When you find out let us know. Oh and there is no such thing as .223 Wylde ammunition. .223 Wylde is a specific chambering that can handle both 5.56 NATO and .223 Remington like VikingsGuy stated. I almost bought a .223 Wylde AR but decided on a 5.56 NATO instead.

 

[JLS]

What these guys said. Cartridge dimensions are identical. The chamber in a 5.56 has a longer leade (distance to the lands) than does a .223 Rem chamber. This allows for the use of higher pressure ammo without blowing up the gun.

 

[44hunter45]

Ditto everyone else.

 

[schmalts]

Now you went and got me all worried. I knew this about the difference in the 2 but now I am second guessing what my barrel actually is in my stainless bull barrel AR.... Taking the front shroud off is a bear too, might have to check just in case LOL I know I have shot both out it and face is still pretty

 

[std7mag]

Go by what is stamped on the firearm, not what the salesman told you.

You could always take it to a smith & have the chamber cut to 223 Wylde.

Puts a longer throat (leade) on it & changes the angle of the lands.

Safe to shoot either 223, or 5.56 with the Wylde chamber.

 

[FLS]

An AR with a standard 223 Remington chamber will be an odd duck. Most are 223/556 , 556, 223 Wylde, occasionally I see a 223 CLE. I would have a competent gunsmith take a look at it.

 

[PsRpOiGrRiAtM]

Some varmint ARs were chambered in .223 for tighter tolerances. What AR do you have, OP?

 

[MO Betta]

The barrel will be stamped with the caliber and usually have the twist rate as well, .223 rem barrels aren't very common for an AR but not unheard of. Everyone else is correct, no 5.56 in a 223 rem rifle. A wylde or 5.56 chambering will shoot both just fine. Also curious about the AR you have.

 

[DamascusSteel]

From my understanding theyre identical except for the internal dimensions of the 5.56 nato. The 5.56 nato case is thicker allowing for higher pressure to achieve the speeds the military desires. But if your AR is 223/556 then you're fine to shoot both in it but if its only 223, Then I wouldn't advise shooting 556 due to higher pressure

 

[Don Fischer]

Had to look this up. Have had about 3 223's, all bolt actions. Have never fired the first military round in any of them but have used MTY military case's to reload. I think Remington making a commercial round that is exactly the same in all outside demention's as a military round is stupid. But same time I have never heard of a problem with the 5.56 being shot in a commercial chamber. But then too, I see this question come up quite a bit. Probably the saving grace is 223 ammo can be had pretty much anywhere and 5.56 can't. Lot of commercial shooter's probably have no idea what a 5.56 is! I wonder how many AR-15 type rifle user's know there might be a difference? Probably more than I think and they probably fire 223's in their AR's not knowing there's a difference. Just looked the 223 and 5.56 up in my Hornady book and the case's are exactly the same size with the exception that the case wall may vary. Well had to look again. One difference between the 223, 223 service rifle and 5.56 is COL. 223 is .010 longer. As I understand it the cartridge orginally developed for the military was not the 223 but rather the 222 Mag and that case is bigger.

But in the case of military ammo being shot in commercial chamber's, I don't do it with anything but do use MTY case's. Have a 6.5x55, 30-06 and 308 and had several of the 223. never the first military round through any of them.

 

[MO Betta]

Had to look this up. Have had about 3 223's, all bolt actions. Have never fired the first military round in any of them but have used MTY military case's to reload. I think Remington making a commercial round that is exactly the same in all outside demention's as a military round is stupid.

FN developed the 5.56 (1970s) based off the .223 Rem (1960s).

 

[PsRpOiGrRiAtM]

The chamber actually differs on the 5.56, which gives it a little more leeway as far as tolerances go. A tighter, commercial .223 chamber will spike pressures on a 5.56 cartridge. That's why the .223 Wylde was developed. Enough slack in tolerances to not drive pressures up, dangerously, but still tight enough to retain as much accuracy as possible.

 

[ImBillT]

The firearm itself can easily handle the pressure spec of a 5.56 NATO, BUUUUTT depending on exactly how a .223 Rem chamber leaves the factory and exactly how the particular lot of 5.56 NATO ammo leaves the factory, it is possible to have an actual chamber pressure that is in excess of the NATO pressure spec when firing 5.56 NATO in a .223 Rem chamber. Personal injury as a result would be quite rare, but there is good reason to stick to the usual advice.

 

[BWALKER77]

The case dimensions for the two are the same except the lead is a little longer for the 5.56. If a round chambers without touching the lands I would have zero issues firing a 5.56 round in a 223. In fact I have without issue.
There is also the issue of barrel twist. Depending on what the twist rate of your 223 barrel and what weight bullet the 5.56 ammo has it may not shoot worth a darn.
But to be honest 5.56 ammo sucks for anything besides burning up ammo at a range.

 

[elkhnter]

Guess I could run in and have Bill explain the whole thing.

 

[shrapnel]

You can bet that lots of 5.56 ammo has been fired in 223 chambered guns with no negative affects. It is by nature that these things will happen, millions of people with millions of guns, what could go wrong?

Here is a good researched article on the differences which really isn’t anywhere near “catastrophic”

5.56 vs .223 - What You Know May Be Wrong - LuckyGunner.com Labs

Andrew of Lucky Gunner Labs explores the differences between .223 Remington and 5.56mm NATO ammunition - and the results may surprise you!

www.luckygunner.com

 

[FAIR CHASE]

All/most of the above explanations may show merit on paper but that is where it ends. With the gazillion rounds of 223/5.56 out there, one would think there would be plenty of kabooms or at least damaged firearms making the forum rounds. It doesn't happen.