I received a Norinco AR15, receiver says 223, paper says 5.56?
- Thread starter Gaebz
- Start date
MANY firearms are marked 223 but ACTUALLY have a 5.56 NATO chamber. This is because marking the firearm as 223 gets around export regulations that restrict the export of firearms with military chamberings.
99.99% chance you're good to go with using 5.56 but if you're not sure get the chamber checked out first.
99.99% chance you're good to go with using 5.56 but if you're not sure get the chamber checked out first.
billbmcleod
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Seriously, has anybody got tocumented proof of a 5.56 going boom in the wrong direction while using factory .233 ammo?
January 1, 2018 by The Arms Guide Guest Writer — 2 Comments
The comparison between .223 and 5.56 isn’t a new one, so there is a lot of discussion to weed through to learn about the two. Ultimately, because they originated from the same cartridge, they are very similar, but that does not mean that they are necessarily interchangeable. This article discusses three key differences between .223 Remington and 5.56x45mm NATO.
.223 Remington and 5.56x45mm Dimension Measurements
At a glance, the two rounds are indiscernible. Both rounds use a bullet of .224in in diameter and an overall length of 2.26in. In general, the external dimensions for the two calibers are identical. What’s more significant is the pressure of the two rounds and the difference in the rifle chambering.
.223 Remington and 5.56×45 Pressure Measurements
One of the problems with comparing these two cartridges is that they utilize different methods of measuring pressure. SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) measures the .223 pressure at the center of the casing, whereas the NATO standard measures the pressure at the throat (or leade) of the chamber. To rectify the two different methods, several have undertaken experiments with their own standardized recording method to compare “apples to apples.” One such thorough study was carried out and recorded in detail by Andrew Tuohy posted via Lucky Gunner Labs (click here to read the full article). Tuohy evaluated various .223 and 5.56 ammo fired through rifles chambered for .223 Remington and 5.56x45mm.
His, and the research of others, confirms that, generally, shooting .223 through a 5.56 chamber results in lower pressure, but still functions (safely). Firing 5.56 through a .223 chamber, however, results in somewhat higher pressures. Although the differences aren’t massive (~5% in the previously referenced study), extensive firing of 5.56 through a .223 chamber could lead to over-pressure malfunctions, such as popped primers or blown cartridge case heads and other firearm malfunctions.
.223 Remington and 5.56×45 Chamber Differences
The most important difference between .223 and 5.56 chambers is the length of the throat (or leade) for each chamber. More specifically, the leade is located at the mouth of the barrel before the rifling occurs. Comparing the NATO and SAAMI regulations, the leade for 5.56 chambers is nearly twice as long as that of a .223 chamber (.162in to .085in, respectively). If a 5.56 round contacts the barrel rifling too early, it can cause pressure spikes (leading to malfunction, and potentially damage) in the chamber. This explains why it is safe to fire .223 through a 5.56 chamber, but not recommended to fire 5.56 through a .223 chamber.
The comparison between .223 and 5.56 isn’t a new one, so there is a lot of discussion to weed through to learn about the two. Ultimately, because they originated from the same cartridge, they are very similar, but that does not mean that they are necessarily interchangeable. This article discusses three key differences between .223 Remington and 5.56x45mm NATO.
.223 Remington and 5.56x45mm Dimension Measurements
At a glance, the two rounds are indiscernible. Both rounds use a bullet of .224in in diameter and an overall length of 2.26in. In general, the external dimensions for the two calibers are identical. What’s more significant is the pressure of the two rounds and the difference in the rifle chambering.
.223 Remington and 5.56×45 Pressure Measurements
One of the problems with comparing these two cartridges is that they utilize different methods of measuring pressure. SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) measures the .223 pressure at the center of the casing, whereas the NATO standard measures the pressure at the throat (or leade) of the chamber. To rectify the two different methods, several have undertaken experiments with their own standardized recording method to compare “apples to apples.” One such thorough study was carried out and recorded in detail by Andrew Tuohy posted via Lucky Gunner Labs (click here to read the full article). Tuohy evaluated various .223 and 5.56 ammo fired through rifles chambered for .223 Remington and 5.56x45mm.
His, and the research of others, confirms that, generally, shooting .223 through a 5.56 chamber results in lower pressure, but still functions (safely). Firing 5.56 through a .223 chamber, however, results in somewhat higher pressures. Although the differences aren’t massive (~5% in the previously referenced study), extensive firing of 5.56 through a .223 chamber could lead to over-pressure malfunctions, such as popped primers or blown cartridge case heads and other firearm malfunctions.
.223 Remington and 5.56×45 Chamber Differences
The most important difference between .223 and 5.56 chambers is the length of the throat (or leade) for each chamber. More specifically, the leade is located at the mouth of the barrel before the rifling occurs. Comparing the NATO and SAAMI regulations, the leade for 5.56 chambers is nearly twice as long as that of a .223 chamber (.162in to .085in, respectively). If a 5.56 round contacts the barrel rifling too early, it can cause pressure spikes (leading to malfunction, and potentially damage) in the chamber. This explains why it is safe to fire .223 through a 5.56 chamber, but not recommended to fire 5.56 through a .223 chamber.
I'm pretty sure that the only important thing in this thread is that OP said he saw 1000 rounds for $315.
Everything else is yesterdays news.
Spill it OP. Where can i get some new ammo that may or may not work in your new rifle?
Everything else is yesterdays news.
Spill it OP. Where can i get some new ammo that may or may not work in your new rifle?
BattleRife
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As it turns out, there is! I present redshooter, with the second best response in the thread:
Of course, the best response was this one:
Isn't 308win and 7.62nato the same? I know there is a small difference between 556 and 223, but I thought 308 and 762 were identical rounds?
At any rate, OP I challenge you to find an example of a gun going kaboom! From using 556 in a 223 chamber. Heard lots of talk, but never heard of a rifle actually breaking...
Of course it's the same difference - when comparing two things there can only be one set of differences!
Alot of manufacturers will mark barrels on rifles as. 223 when in actuality they are 5.56 caliber. The reason for this is because .223 is considered a civilian round whereas 5.56 is used by numerous militaries. It is easier to export .223 rifles then 5.56 ones. It all comes down to making the process easier for exporters and importers.
Like GoTenda said, they are milspec 5.56 chamber rifles with 223 on the barrel. These are not 223 even if 223 is written on them.
GoTenda over the phone told me they sold Norinco CQAs for 10 years and they are all 5.56 milspec chamber rifles. Even if it’s 223 on the barrel. And no one in 10 years called for a problem related to this. They are sold as 5.56 on the bill.
