5.56/223 ammo question

[Remington742]

I recently acquired a bushmaster qrc. It says it is chambered 5.56/223. I have heard that shooting 223 ammo out of a 5.56 chambered gun can damage the gun but I am not sure if that is true or not. Any help with this would be greatly appreciated thanks in advance.

 

[TNRifleman]

.223 out of a 5.56 is not bad. You don't want to shoot 5.56 out of a gun stamped solely .223

 

[MUP]

^^^This.

 

[Remington742]

Thanks. I also meant to ask I have read that the 223 bullet is smaller than the 5.56 and when you shoot the 223 out of the 5.56 chamber that the 223 round will damage the rifling is that true.

 

[7mminatree]

Bullets in 5.56 and .223 are the same diameter, which is .223. Only the weights are different. If your rifle is marked for .223/5.56 NATO your good to go for any ammo in that caliber. Your rifle may not stabilize some of the heaviest bullets if it's a 1:9 twist, but no harm will be done to the barrel. Pick you up a bunch of XM193 55gr ammo. It shoots great in just about any AR made.

 

[MUP]

Well, the .223 I believe is just as it says it is in dia, maybe .224". The 5.56 is .219", going just by the 5.56 and converting to inches. So it is smaller, but not sure about the damage it may or may not cause. I'm sure someone will chime in who knows.

 

[MUP]

Hmmmm. Did not know that 7mminatree. I wonder why it's marked 5.56 then, when it could be 5.66 or 5.67?

 

[DaveB]

The bullet for either caliber is .224.

The exterior size of both rounds is exactly the same or so close the difference is less than manufacturing tolerances.

The difference is inside the brass. The 556 has higher internal pressure. It is that difference that causes all the warnings.

Also, there is no SAAMI spec for 556, only 223. If you give that a thought, you realize there are no boundaries for the 556. It can be loaded hot, intended for a specific use (think mini-gun) or the brass could be thicker to support the hotter charge.


Edit: I found this article which is wroth reading
http://www.luckygunner.com/labs/5-56-vs-223/

 

[7mminatree]

Well, the .223 I believe is just as it says it is in dia, maybe .224". The 5.56 is .219", going just by the 5.56 and converting to inches. So it is smaller, but not sure about the damage it may or may not cause. I'm sure someone will chime in who knows.

Your right bullet dia. Is .224 for both rounds but the .219 is no where in the blue printed 5.56 case dimensions. Maybe they rounded down. I'm not sure.

 

[7mminatree]

DaveB,
Also as of late I've measured some case volumes and weight of some 5.56 cases that were identical to commercial .223 brass. The foreign 5.56 can be all over the map, but the Lake City brass is is definitely for the higher pressure loads.

Mup, I see .219 as the pilot diameter.

 

[DaveB]

I only load H335 in my 223 brass and Cannot tell the difference in case capacity like I can with my 308. But I sure can tell when small base re-sizing the once fired crimped primer military stuff. Whole lot more arm and you better use a good lubricant or you have stuck cases. Trust me on that one.

 

[7mminatree]

I only load H335 in my 223 brass and Cannot tell the difference in case capacity like I can with my 308. But I sure can tell when small base re-sizing the once fired crimped primer military stuff. Whole lot more arm and you better use a good lubricant or you have stuck cases. Trust me on that one.

Imperial wax :tu:

 

[MUP]

DaveB,
Also as of late I've measured some case volumes and weight of some 5.56 cases that were identical to commercial .223 brass. The foreign 5.56 can be all over the map, but the Lake City brass is is definitely for the higher pressure loads.

Mup, I see .219 as the pilot diameter.

Aha!

 

[rtaylor]

In layman's terms if your gun is 5.56 it can shoot either bullet. Your gun is designed to shoot either so find a bullet for a good price and hit the range.

 

[Remington742]

Thankyou guys that helps a bunch.

 

[pullemfar]

.223 out of a 5.56 is not bad. You don't want to shoot 5.56 out of a gun stamped solely .223

Yepper^^^^^