.223 Remington vs 5.56 Mil.

[Ronvandyn]

So, the question has come up, where is the difference between these two rounds.  I did some research when I initially thought about getting a .223 and there was much discussion but little definitive information.  I am now in a position to buy some 5.56 but have no wish to blow out my rifle with the wrong rounds. 

Can anyone point me in the direction of a definitive answer on this?  I dont mind buying the 5.56 because I can always resell it to someone with an AR (plenty of you guys out there, right?  ).

Ron

[RobertH]

from what i know/remember... .223Remington and 5.56x45 are the same in looks, but perform differently.  the 5.56 have a lot higher chamber pressures, therefore it could blow your gun apart.  maybe not on the first or second or even 20th round, but it stresses out the chamber.

on AR15's, the end of the barrel by the flash hider would say something like ".223Rem/5.56", then both calibers are ok.  always take the side of caution.

anyone else have other information?

[justsomeguy]

anyone else have other information?

Yep... The people who make firearms and ammunition say don't do it.

http://www.saami.org/specifications_and_information/publications/download/SAAMI_ITEM_211-Unsafe_Arms_and_Ammunition_Combinations.pdf

[Dan W]

5.56 chambers are not the same as .223

Get a 5.56 chambered rifle, or the compromise Wylde chamber if you want to shoot any type of ammo.

I would not recommend shooting 5.56 ammo in a tight .223 chamber, as the risk is blown out primers and extraction problems, and in the worst case possible high pressure failures of the chamber.

5.56 ammo needs more room in the leade where the bullet extends into the rifling. when firing 5.56 ammo in a tighter match .223 chamber, it is possible for the neck to pinch the bullet at the leade and cause a very high pressure spike before the bullet exits

[Mudinyeri]

Nice discussion guys.  Usually when I see this topic on forums, it's accompanied by the "I shoot 5.56 out of my .223-chambered rifle all the time and have never had a problem" comments.

While that may be true, it's safest to shoot only the ammo for which your gun was chambered. 

One other point of clarification: Not all AR's are chambered for 5.56.  Check the barrel, not the lower for chambering markings.  It makes no difference whatsoever what the markings are on the lower. 

[Rodney Moorhead]

I was wondering, would it just be a solution to get a 5.56 chamber reamer and open up the .223 chamber?

[Dan W]

I was wondering, would it just be a solution to get a 5.56 chamber reamer and open up the .223 chamber?

It can be done, but it kinda defeats the purpose of a chrome lining in the chamber.

[Ronvandyn]

Yeah, RobertH and I discussed it last night a bit and I decided to pass on the 5.56.  The 223 rounds are a good deal and we will be discussing those tonight. 

I spent years shooting 5.56 as an Airforce Security Policeman and was always of the opinion that they were just about the same.  Reading the velocity specs of the standard 223 tells me that there is a small difference somethere but I was not real sure where.  I spent far to much on my rifle to blow the chamber on an experiment, so I'll stick with what I know works. 

Ron

[00BUCK]

Yeah, RobertH and I discussed it last night a bit and I decided to pass on the 5.56.  The 223 rounds are a good deal and we will be discussing those tonight. 

I spent years shooting 5.56 as an Airforce Security Policeman and was always of the opinion that they were just about the same.  Reading the velocity specs of the standard 223 tells me that there is a small difference somethere but I was not real sure where.  I spent far to much on my rifle to blow the chamber on an experiment, so I'll stick with what I know works. 

Ron

But why limit yourself? Just because .223 rounds may be a good deal today doesn't mean you might not find a great deal on some 5.56 ammo down the road - Which you will have to pass up if you buy a .223 chambered AR.

[Ronvandyn]

But why limit yourself? Just because .223 rounds may be a good deal today doesn't mean you might not find a great deal on some 5.56 ammo down the road - Which you will have to pass up if you buy a .223 chambered AR.

I'm not a big fan of the "SHTF" theory, and for the money I spent on my new rifle I most likely could have gotten 2 AR's.  I lost my facination with "black rifles" in the military and now shoot strictly for pleasure.  Its relaxing to sit there and pop one off at a time, slowly, while enjoying the day (as long as I dont bring the kids along, then its a pain).  Its the same reason I also shoot muzzle loaders, just for the joy of it. 

Although I do seem to be growing an itch for an M-1 Carbine.  Kinda weird, my Dad had one when I was a kid and I loved it.  If I can find a good one for the right price I think I might add it to my growing collection.

Ron

[Clint]

I really thought they were the same rounds. I have an old mini-14 that I have shot both rounds through. I see the newer ones are OK, but I need to dig mine out and see if it is really chambered for both like the newer ones are. They are SO dang close...

[FarmerRick]

Physically, the brass is a little different too, as 5.56 usually has thicker walls near the base.


Another good chart: