.233 vs 5.56 pressure
- Thread starter Virtual.Chris
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Falconflyer
CGN Ultra frequent flyer
Hornady explains this.
From their website.
Differences between the two are small but can have a large impact on performance, safety and weapon function.
The first difference is the higher pressure level of the 5.56 NATO cartridge which runs at approximately 58,000 psi. A 223 Remington is loaded to approximately 55,000 psi.
The second and most important difference between the two is the fact that a 5.56 NATO chamber has a .125” longer throat. This allows approximately one more grain of powder to be loaded into a 5.56 NATO cartridge; this is what gives it higher performance than its 223 Remington cousin.
The biggest problem with these differences is when firing a 5.56 NATO cartridge in a rifle chambered for 223 Rem. Due to the longer throat that the NATO chamber employs this combination will cause a 223 chambered weapon to run at approximately 65,000 psi or more. This is 10,000 psi higher than the 223’s normal functioning pressure of 55,000 psi. This is NOT safe and will cause primers to back out, or worse, cause harm to the operator, the rifle, or both.
The reverse of this is firing a 223 Rem cartridge in a 5.56 NATO chambered rifle. Due to the throat difference between the two chambers a 223 Rem cartridge may not work optimally in a 5.56 NATO chambered weapon. The cause of this is the lack of pressure built by a 223 Rem cartridge fired from a 5.56 NATO chamber. The 223’s 55,000 psi will not be attained and therefore velocity and performance are hurt. Problems start occurring when this combination is fired out of a 5.56 NATO chambered rifle with a 14.5” (or shorter) barrel. The lower powder charge of the 223 round coupled with the pressure drop that occurs when it is fired in a the 5.56 NATO chamber will cause the rifle to cycle improperly. NATO chambered rifles with barrels longer than 14.5” should function properly when firing 223 Rem ammunition.
From their website.
Differences between the two are small but can have a large impact on performance, safety and weapon function.
The first difference is the higher pressure level of the 5.56 NATO cartridge which runs at approximately 58,000 psi. A 223 Remington is loaded to approximately 55,000 psi.
The second and most important difference between the two is the fact that a 5.56 NATO chamber has a .125” longer throat. This allows approximately one more grain of powder to be loaded into a 5.56 NATO cartridge; this is what gives it higher performance than its 223 Remington cousin.
The biggest problem with these differences is when firing a 5.56 NATO cartridge in a rifle chambered for 223 Rem. Due to the longer throat that the NATO chamber employs this combination will cause a 223 chambered weapon to run at approximately 65,000 psi or more. This is 10,000 psi higher than the 223’s normal functioning pressure of 55,000 psi. This is NOT safe and will cause primers to back out, or worse, cause harm to the operator, the rifle, or both.
The reverse of this is firing a 223 Rem cartridge in a 5.56 NATO chambered rifle. Due to the throat difference between the two chambers a 223 Rem cartridge may not work optimally in a 5.56 NATO chambered weapon. The cause of this is the lack of pressure built by a 223 Rem cartridge fired from a 5.56 NATO chamber. The 223’s 55,000 psi will not be attained and therefore velocity and performance are hurt. Problems start occurring when this combination is fired out of a 5.56 NATO chambered rifle with a 14.5” (or shorter) barrel. The lower powder charge of the 223 round coupled with the pressure drop that occurs when it is fired in a the 5.56 NATO chamber will cause the rifle to cycle improperly. NATO chambered rifles with barrels longer than 14.5” should function properly when firing 223 Rem ammunition.
Basically I honestly don't believe that anyone will make a 223 calibre rifle that cannot stand the pressures of 5.56. It would be stupid.
Every manufacturer knows that we don't give a .... and will just stick ammo into our guns. They know for example that people manage to put 300 blackout into 5.56/223 guns and shoot it (which does cause a big bang) so they know that we aren't going to meticulously stick to separating our 5.56 and 223 rifles and ammo from one another when visually they are identical
I'm not a super expert but I cannot recall or find a single example of it ever being a problem.
Every manufacturer knows that we don't give a .... and will just stick ammo into our guns. They know for example that people manage to put 300 blackout into 5.56/223 guns and shoot it (which does cause a big bang) so they know that we aren't going to meticulously stick to separating our 5.56 and 223 rifles and ammo from one another when visually they are identical
I'm not a super expert but I cannot recall or find a single example of it ever being a problem.
Gunnerlove
CGN Ultra frequent flyer
- Location
- Vancouver Island
Umm. My 223 ruger will not eat 5.56. It pops primers.
YMMV is a real thing.
YMMV is a real thing.
Got any proof of that? Bit of a bone Q given the OIC but worth asking.
If not then feel free to link us to literally any evidence of this actually happening and not just articles warning about it happening
I've read all of the points and counter points and I have shot 556 through a 223 savage axis with no popped primers, no exploded receivers and decent groups downrange. I've even reloaded the 556 brass afterwards as they were in perfect condition. In my experience, with Savage anyway, the 223 is probably over engineered knowing cowboys are going to shoot 556 through it. No issues.
All I wanted to know is the pressure difference... and if it’s noticeable to the shooter. Why did this have to turn into a thread on shooting different calibers from different chambers?
Let me try this again... can anyone tell the difference in recoil, noise, etc between a .223 and a 5.56 round... for those of you who have safely shot both from the same weapon?
Let me try this again... can anyone tell the difference in recoil, noise, etc between a .223 and a 5.56 round... for those of you who have safely shot both from the same weapon?
You may not notice it, unless you are taking velocity readings with a chrony, or you are seeing evidence of over pressure on the spent brass, or the action of your auto loader is acting up.
Firing pin holes in primers and popped primers are obvious & overt signs of overpressure.
Can your rifle handle it? Quite likely - the engineering is there to handle overpressure in most quality built barrels and actions with proofing rounds, but making a habit of doing it is a pretty dumb idea.
If the Ruger is a tight .223 chamber, I'd either keep to handholds or chase it with reamer, depending what I wanted from it and what I wanted to feed it.
Not that this will be a popular statement and I am sure to get flamed for it but here it goes.
I have shot tens of thousands of 556 in 223 Savage, Ruger, Tikka, and Remington bolt rifles for more than 3 decades and I have all my fingers and eyeballs.
I once took a rifle to one of the best gunsmiths in the Maritimes to get a 223 chamber reamed to 556. He told me not to bother, that 556 would be safe in the 223 despite all that is written. It would just make the rifle shoot 223 less accurate. He was right. The recoil is not any different and the rifle will shoot fine and safe. Bang away. Can I say that?
Cheers
Moe
I have shot tens of thousands of 556 in 223 Savage, Ruger, Tikka, and Remington bolt rifles for more than 3 decades and I have all my fingers and eyeballs.
I once took a rifle to one of the best gunsmiths in the Maritimes to get a 223 chamber reamed to 556. He told me not to bother, that 556 would be safe in the 223 despite all that is written. It would just make the rifle shoot 223 less accurate. He was right. The recoil is not any different and the rifle will shoot fine and safe. Bang away. Can I say that?
Cheers
Moe
Thanks guys.
. I was really just curious if the 223 had noticeably less pressure in recoil, gas system wear, etc compared to 5.56 (assuming both were shot from a 5.56 or Wylde chamber) but it sounds like the difference is only about 5% which isn’t going to be noticeable.They were a hot topic a while back; but I read a bunch of articles and reviews back when I was building my AR, and results were mixed, with the extra cost being high. I decided to ignore the hype, avoid the controversy, a buy a cheap Dominion barrel. No issues with either, and it was a tack driver; now languishing in the safe.
