5.56mm in .223REM rifles: What's the real story?

[phillyblt]

556 has more pressure thats it

So use 556 in 556 and 223 in 223

 

[fred0000]

Norinco settled the debate in the 90's
Their yellow box 223 remington everyone likes cause "it's hot" is the exact same stuff as the white box with 5.56x45 printed on it.
Their 223 is hot, cause it's 556

 

[toebako]

If 223 and 556 could not be mixed and used then think how many american lawsuits there would have been. It’s fine or you would have heard all about it and one would have been made extinct.

 

[monahov]

If shooting .223 in a 5.56 chamber or shooting 5.56 in a .223 chamber was a problem there would be thousands of pictures on the internet of blown up rifles and disfigured shooter.

It doesn't need to be a catastrophic failure in order for this still to be a problem (I mean 5.56NATO in .223). The typical pattern is this - it shoots, but the higher pressure results in primer popping out. Casing gets extracted, but the primer gets stuck in the locking lugs. The next round is fed, and while the bolt fails to close on it to be in battery, the bolt gets stuck. This might be not a big deal in bolt action, but it may be pretty problematic in semi-auto. If you are lucky to have your charging handle attached to BCG, you hammer it to pull the bolt out. It still grabs the cartridge by the rim and spills some powder, and the bullet gets stuck in the chamber. Then, if you have a long cleaning rod at hand, you can push it out. While this may be entertaining once (if you are not busy with anything more important), it would be rather annoying if you needed it to perform reliably.

 

[fred0000]

The one you gotta be worried about is .300blackout in a 556/223 chamber, this one's definitely not a "if it fits, it ships" situation.

 

[maynard]

It doesn't need to be a catastrophic failure in order for this still to be a problem (I mean 5.56NATO in .223). The typical pattern is this - it shoots, but the higher pressure results in primer popping out. Casing gets extracted, but the primer gets stuck in the locking lugs. The next round is fed, and while the bolt fails to close on it to be in battery, the bolt gets stuck. This might be not a big deal in bolt action, but it may be pretty problematic in semi-auto. If you are lucky to have your charging handle attached to BCG, you hammer it to pull the bolt out. It still grabs the cartridge by the rim and spills some powder, and the bullet gets stuck in the chamber. Then, if you have a long cleaning rod at hand, you can push it out. While this may be entertaining once (if you are not busy with anything more important), it would be rather annoying if you needed it to perform reliably.

Up until the early 90's the DND issued ammo for DCRA and PRA shooting competitions. Lots of shooters built .223 rifles it take advantage of the better quality 5.56 ammo (until the DND fixed this and made 5.56 ammo shoot just a $hitty and the 7.62 ammo)
Do you think the DND would issue ammo that was dangerous knowing that 5.56 ammo was being fired in .223 rifles? The cadet program also shot 5.56 ammo in there .223 target rifles. Do you thing the DND would allow this if there was a safety concern?

fred0000, looking at those pictures I would say that it was more than likely a round loaded with the wrong powder than a .300 BLK loaded into a .223 chamber. Hard to believe that a round that is approximately .080" larger diameter would fit into .223 chamber and allow the bolt to go into battery. And what is that long copper thing in the picture? Can't be a bullet, it is longer than the case.

 

[tiriaq]

Up until the early 90's the DND issued ammo for DCRA and PRA shooting competitions. Lots of shooters built .223 rifles it take advantage of the better quality 5.56 ammo (until the DND fixed this and made 5.56 ammo shoot just a $hitty and the 7.62 ammo)
Do you think the DND would issue ammo that was dangerous knowing that 5.56 ammo was being fired in .223 rifles? The cadet program also shot 5.56 ammo in there .223 target rifles. Do you thing the DND would allow this if there was a safety concern?

fred0000, looking at those pictures I would say that it was more than likely a round loaded with the wrong powder than a .300 BLK loaded into a .223 chamber. Hard to believe that a round that is approximately .080" larger diameter would fit into .223 chamber and allow the bolt to go into battery. And what is that long copper thing in the picture? Can't be a bullet, it is longer than the case.

That is what happens when a .300B is fired in a 5.56 rifle. I have personally seen one such specimen. Didn't see it happen, of course, just saw the results. The forward assist might be needed to get the breech closed.

 

[tiriaq]

It doesn't need to be a catastrophic failure in order for this still to be a problem (I mean 5.56NATO in .223). The typical pattern is this - it shoots, but the higher pressure results in primer popping out. Casing gets extracted, but the primer gets stuck in the locking lugs. The next round is fed, and while the bolt fails to close on it to be in battery, the bolt gets stuck. This might be not a big deal in bolt action, but it may be pretty problematic in semi-auto. If you are lucky to have your charging handle attached to BCG, you hammer it to pull the bolt out. It still grabs the cartridge by the rim and spills some powder, and the bullet gets stuck in the chamber. Then, if you have a long cleaning rod at hand, you can push it out. While this may be entertaining once (if you are not busy with anything more important), it would be rather annoying if you needed it to perform reliably.

Have you actually seen or experienced this happen?
If you want to compare maximum specified pressure levels (which are not the same as typical working pressures) have a look at the specs for SAAMI and CIP .223 ammunition.

 

[lucky07]

fred0000, looking at those pictures I would say that it was more than likely a round loaded with the wrong powder than a .300 BLK loaded into a .223 chamber. Hard to believe that a round that is approximately .080" larger diameter would fit into .223 chamber and allow the bolt to go into battery. And what is that long copper thing in the picture? Can't be a bullet, it is longer than the case.

Why do people argue just for the sake of arguing?

You can literally see the headstamp of the case while it's still in the chamber. And a proper sized barrel wouldn't have extruded the bullet like that so pretty safe to assume it wasn't fired though such a barrel.

 

[monahov]

Have you actually seen or experienced this happen?
If you want to compare maximum specified pressure levels (which are not the same as typical working pressures) have a look at the specs for SAAMI and CIP .223 ammunition.

Yes, I experienced this myself at least twice with a rifle chambered in .223. I can also tell, that the bolt doesn't close on 5.56 "Go" gauge in that chamber.