.223/5.56 confusion
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MO Betta
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Some of the later replies seem to only be focusing on potential for catastrophic failure/injury. The potential is there, if only a slight chance, up to you if it is worth the risk to use them.
With higher pressure you're inducing more stress, and with an AR that leads to premature failure of parts. Especially the bolt and extractor.
With higher pressure you're inducing more stress, and with an AR that leads to premature failure of parts. Especially the bolt and extractor.
Its hard to find an AR chambered in 223. In fact I have never seen one.
It's also hard to find a 223 chambered with a SAAMI minimum throat.
MO Betta
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It is nowadays, which is why some of us asked what is stamped on the barrel.
What is nowadays?
NV_ARCH3R
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It's a Colt Match Target. Nothing stamped on the barrel unless it's under the handguard, but the lower is stamped 223
shrapnel
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This is the inquiry..
Risk is somewhat nebulous, and addressed as a possibility for catastrophic failure because that is what the ultimate concern is. If you want to see high chamber pressures, you can find it with Weatherby factory ammunition.
SAAMI pressures are a measuring standard to determine tolerances in action strength. If you actually read the posted article and the data that was supplied there, you would see the charts and what the pressure curves with different actions and chambers are. That was done with equipment made to test the physics of what goes on in a rifle chamber, not some hyperbole from rumors.
I would submit that the scare of unsafe stress on an action between the 2 chamberings is more a concern of barrel erosion and accuracy of one ammunition type over the other...
Risk is somewhat nebulous, and addressed as a possibility for catastrophic failure because that is what the ultimate concern is. If you want to see high chamber pressures, you can find it with Weatherby factory ammunition.
SAAMI pressures are a measuring standard to determine tolerances in action strength. If you actually read the posted article and the data that was supplied there, you would see the charts and what the pressure curves with different actions and chambers are. That was done with equipment made to test the physics of what goes on in a rifle chamber, not some hyperbole from rumors.
I would submit that the scare of unsafe stress on an action between the 2 chamberings is more a concern of barrel erosion and accuracy of one ammunition type over the other...
MO Betta
Well-known member
Those are typically 5.56 even though the lower is stamped .223. Your barrel should say C MP 5.56 Nato between the gas block and muzzle if the barrel hasn't been replaced.
@BWALKER77 past couple decades? Not saying they were commonplace, but they were used on some models. The Remington R15, S&W MP15Is and DPMS bull barrel come to mind. Up until the Wylde hit the scene most barrel makers I buy from had a .223 Rem offering for ARs.
MO Betta
Well-known member
My response was worded poorly. I was going along the lines that even if you choose to believe there is no risk of injury associated to the use of 5.56 in an actual .223 chamber, you are more likely to have greater wear and tear on the firearm from the higher pressure.
I'll have to read that article further when I get a chance. Quick glance seems to defy what I've always been told was the gospel.
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shrapnel
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Not having access to a laboratory and the equipment to do the testing that was done for that article, will leave you subject to other data that is hard to prove or disprove. Speculation and rumor does give people the wrong information and often times it gets spread as fact.
I haven’t had any experience myself with the conflict between the 2 rounds, but just by sheer numbers of 223 chambered guns, you can extrapolate without much error, that plenty of people would have mixed the 2, back and forth with no real danger to the user. Had there been a catastrophic disaster, it would have been known and some kind of recall or industry warning would have been implemented.
If nothing else a toilet paper shortage would have been an indicator...
Exactly.
NV_ARCH3R
Active member
K, the barrel is stamped C MP 5.56 NATO 1/7. So from what I'm hearing it is actually chambered for 5.56 not just a 223 chambering.
Maybe this will help folks visualize it.
Theoretically you could be over pressure shooting 5.56 in a 223 Rem. Having done this thousands of times, I don’t worry about it. But I also don’t shoot 100 rounds per minute in 100 degree heat either.
Don Fischer
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I don't know one person that has pressure testing equip at home, never have known one. Never even knew a gunsmith that had it. Leaves me to think no one has a clue what kind of pressure they are getting. What every rifle I ever saw had was the cartridge it's designed for stamped on the barrel. That is what to look for and simply dont fool with it. I've never fired a military round of any knid in a commercial rifle but have used a lot of military case's over the years. Never had a problem. I never did that because of difference's claimed in pressure, I did it because I don't like firing fmj bullet's! Forget the case and consider the action, doubt the M-16 action could hold up to the pressure of a commercial bolt action. But swapping out ammo for a cartridge not stamped on the barred could well be playing with fire.
5.56 rated at 65k I wonder what happens when the bullet pass's over the gas port? I don't think any cartridge get's to it made pressure that soon after firing. Just wondering if the thing reach's maybe just a bit past the gas port and siphons off pressure? Then while the case may be made to handle 65k it never actualy has to in the military chamber.
This is of course just a bunch of BS I couldn't prove so for me the bottom line would be son't put a cartridge designed for something other than stamped on the barrel in the rifle and shoot it. Might find speculation fly's right out the window then! If the barrel is marked 223, shoot 223 in it. If your being charged by a rabid sage rat and all you have is one 5.56 round for your 223, hit it over the head with your stock! If your handloading 5.56 case's for your 223, go for it but remember to start low and work up. I'd about bet if you hooked up something to fire pressure into both case's without having them supported bu a steel chamber, neither case would contain even 50k pounds of pressure. The case is nothing more than a liner in the chamber that holds the components! A lot of the things we see are measured with equipment we don't have. In that case we operate on blind faith! Guy's measuring pressure with their chronograph is silly. They are not easuring pressure they are measuring velocity and assuming at a certain velocity they have a certain pressure. What you can be certain of is if your rifle blow'sup, up had to mush pressure for one reason or another!
5.56 rated at 65k I wonder what happens when the bullet pass's over the gas port? I don't think any cartridge get's to it made pressure that soon after firing. Just wondering if the thing reach's maybe just a bit past the gas port and siphons off pressure? Then while the case may be made to handle 65k it never actualy has to in the military chamber.
This is of course just a bunch of BS I couldn't prove so for me the bottom line would be son't put a cartridge designed for something other than stamped on the barrel in the rifle and shoot it. Might find speculation fly's right out the window then! If the barrel is marked 223, shoot 223 in it. If your being charged by a rabid sage rat and all you have is one 5.56 round for your 223, hit it over the head with your stock! If your handloading 5.56 case's for your 223, go for it but remember to start low and work up. I'd about bet if you hooked up something to fire pressure into both case's without having them supported bu a steel chamber, neither case would contain even 50k pounds of pressure. The case is nothing more than a liner in the chamber that holds the components! A lot of the things we see are measured with equipment we don't have. In that case we operate on blind faith! Guy's measuring pressure with their chronograph is silly. They are not easuring pressure they are measuring velocity and assuming at a certain velocity they have a certain pressure. What you can be certain of is if your rifle blow'sup, up had to mush pressure for one reason or another!
MO Betta
Well-known member
Correct, with that twist rate you'll more than likely find that it shoots heavier projectiles more accurately. 60-70 grain and above.
FAIR CHASE
Well-known member
More merit discussing 300 BO in 223.
Or 22 lr in 22 mag cylinder ...... could I, should I
Or 22 lr in 22 mag cylinder ...... could I, should I
Mark1970
Member
Ha!
This is a long standing debate. I recall reading a good article on it years ago. I hunted it down so that I could share it. It was done by Luckygunner Labs. They did a nice investigation, including chamber pressures and gun to gun variation.
https://www.luckygunner.com/labs/5-56-vs-223/
My interpretation of the study is that it really does not matter when it comes to chamber pressure.
That said, there is an entire other difference which is barrel twist.
.223 rifles normally come with a 1:10 or 1:11 twist for lighter (55g and less), faster projectiles.
5.56 rifles normally come with a 1:7 or 1:8 twist for slower, heavier (55g and more) projectiles.
Most .223 ammo has lighter projectiles and most 5.56 has 62g penetrators.
So to me its semantics. If I want a 45g bullet for a 1:11 twist rifle, both the rifle and the ammo will likely be called .223 (but if they are called 5.56, I am OK with that.
If I want to shoot a heavier bullet in a 1:7 twist rifle, both cartridge and rifle will probably be stamped 5.56, but I am OK if they say something different.
If I shoot heavy bullets, which fly slower, in a 1:11 twist barrel, they may not have enough spin to stabilize. This can lead to poor groups and key-holes on the paper target.
If I shoot lighter bullets, which fly faster, in a 1:7 twist barrel, I have read, that they can spin so fast that they fling off their copper jacket. I found this hard to believe until I was at the 100 yard range and found a bunch of what looked to be .223 copper jackets all about 30 yards down range of the firing line. So maybe that is exactly what I witnessed..... maybe. Who ever fired them was no longer there that day so I could not ask them what they were shooting.
This is a long standing debate. I recall reading a good article on it years ago. I hunted it down so that I could share it. It was done by Luckygunner Labs. They did a nice investigation, including chamber pressures and gun to gun variation.
https://www.luckygunner.com/labs/5-56-vs-223/
My interpretation of the study is that it really does not matter when it comes to chamber pressure.
That said, there is an entire other difference which is barrel twist.
.223 rifles normally come with a 1:10 or 1:11 twist for lighter (55g and less), faster projectiles.
5.56 rifles normally come with a 1:7 or 1:8 twist for slower, heavier (55g and more) projectiles.
Most .223 ammo has lighter projectiles and most 5.56 has 62g penetrators.
So to me its semantics. If I want a 45g bullet for a 1:11 twist rifle, both the rifle and the ammo will likely be called .223 (but if they are called 5.56, I am OK with that.
If I want to shoot a heavier bullet in a 1:7 twist rifle, both cartridge and rifle will probably be stamped 5.56, but I am OK if they say something different.
If I shoot heavy bullets, which fly slower, in a 1:11 twist barrel, they may not have enough spin to stabilize. This can lead to poor groups and key-holes on the paper target.
If I shoot lighter bullets, which fly faster, in a 1:7 twist barrel, I have read, that they can spin so fast that they fling off their copper jacket. I found this hard to believe until I was at the 100 yard range and found a bunch of what looked to be .223 copper jackets all about 30 yards down range of the firing line. So maybe that is exactly what I witnessed..... maybe. Who ever fired them was no longer there that day so I could not ask them what they were shooting.
shrapnel
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The biggest problem with debates such as this is how little people read what is being discussed. Case in point, check post #19...
Now that's funny.
