The 223 Rem cartridge may not perform optimally in NATO 5.56 firearms due to the throat difference between the two chambers. The biggest problem with these differences comes when firing 5.56 NATO to 223 Rem. Since both are cartridges, the main problem with these differences is when firing the 5.56 NATO cartridge into a 223 Rem loaded rifle. Therefore, at lower pressures, the .223 can be safely used in a 5.56mm NATO standard rifle, but not the other way around.
The fact that the barrel is engraved with .223 Rem./5.56 NATO does not mean that it can work equally well with both types of ammunition. If the rifle has 5.56 NATO rounds, you can use .223 Remington or 5.56 NATO rounds. You can easily swap two rounds for a 5.56 NATO rifle.
The chamber in the 5.56 is designed to withstand high pressure, while the chamber in the .223 is less pressure. Note that 5.56 cannot fire from chamber 223, but chamber 223 can fire from chamber 556 due to pressure differences. The 5.56 has a longer throat, which gives less pressure than the same cartridge chambered in .223. Although the 223 can be chambered at 5.56, it will have a lower velocity due to the lower pressure.
The 5.56 NATO caliber has a higher pressure than the 223 cartridge, and this is one of two main differences. Testing methods vary, but the most accurate test showed the 5.56 NATO had 5,000 psi more pressure than the .223. It is difficult to accurately compare the licensed pressures of the two cartridges because the .223 Remington is standardized by the Sporting Weapons and Ammunition Manufacturers Institute (SAAMI), but the 5.56x45mm cartridge is not.
The .223 Rem and 5.56 NATO maximum pressures of 55,000 and 62,000 psi, respectively, does not mean that ammunition will actually be charged at that pressure. In practice, this means you won’t be able to get the most out of true 5.56 NATO ammunition unless your rifle is built to NATO specifications such as lead, RPM and can handle slightly more chamber pressure. I can say that a 5.56 bolt-action NATO chambered rifle will have no problem shooting .223, but if it is a semi-automatic version of the AR-15 / M-16 pistol, the pistol may not work at lower pressures. .223. …
It should also be noted that some chambers made for the .223 start out sharper, which can cause some pressure issues with the rifle when using 5.56 rounds. In particular, the Remington .223 chamber is generally smaller and has a shorter bore or free bore (the distance between the case mouth and the point where the rifling engages the bullet) at a steeper angle than the 5.56mm chamber. Many rifles are more accurate with shorter leads, but others prefer longer bullet jumps. The biggest difference between 5.56 and .223 cartridges is speed based appearance and final performance.
It is true that the .223 barrel showed about 5% more pressure at less than 1% higher than the 5.56 barrel at the lower pressure / slow speed, but the difference was not surprisingly large as some might have expected. Using this method, measuring the pressure difference between 5.56 and 223 made it easy to conclude that 5.56 has a much higher pressure in psi than 223.
The notable difference between the two is that the 5.56 has a higher pressure level, around 58,000 psi. The main difference is that the 5.56x45mm NATO cartridge operates at a higher chamber pressure (~60,000 psi). The first difference is the higher pressure level of the 5.56 NATO cartridge, which operates at about 58,000 psi.
In the .223 Remington rifle, the bullet creates chamber pressure in excess of 70,000 psi, which meets SAAMI (Sporting Weapons and Ammunition Manufacturing Institute) standards. The .223 Remington’s chamber size creates a tighter fit to the bullet and therefore creates more pressure despite firing bullets of the same size from the same case, with a slightly warmer powder charge as more gas is released with the larger lead. This 5.56 NATO chamber size is actually slightly larger than the .223 Rem chamber, so you have smoother feeding and ejection, even from dirty weapons, which will best serve you as a weapon of combat – but this is the basic dimension that has highest value.
For those interested in lead, the distance between the muzzle of the cartridge and the point of contact of the rifling with the bullet is called. Hence the long-range round, or the lead round, fired from the chamber with a shorter lead, as in the case of NATO 5.56 rounds from the .223 Rem. Your pistol must be chambered for NATO or Mil-Spec with a longer lead.
This is achieved by scaling the chamber to the same lead length as 5.56mm NATO, but with a free bore .223 Remington bore. In between are chambers designed to balance pressure and accuracy, as the 5.56 NATO chambers’ long free passage and throat dimensions are often accused of being less accurate than Remington .223 chambers. This is because the 5.56 NATO and .223 Remington rifles have different chamber sizes.
For the same reason, all manufacturers that do not use Wylde .223 cameras use 5.56 camera sizes. However, given the general differences in cartridges and chambers, it is recommended not to use 5.56mm ammunition in firearms with a dedicated .223 chamber. In 1979, SAAMI warned that the 5.56 caliber chambers were different from the .223 sporting rifles, and that the use of 5.56 rounds in .223 rifles could increase the pressure to dangerous levels. Since, other things being equal, shorter strokes result in higher chamber pressures than longer strokes, this means that firing 5.56mm cartridges (which are already loaded at higher pressure) from the Remington .223 chamber can result in dangerous enlargement of the chamber. pressure.
When you fire the .223 into the 5.56 NATO chamber, the optimum 55,000 psi will not be achieved, speed, thermal ballistics and performance will suffer. The difference that usually makes the .223 lower pressure is that it is governed by the SAAMI specification, which generally reduces bullet pressure in the market. If we adhere to NATO and European standards, their ammunition is usually loaded at a higher pressure. NATO munitions, on the other hand, are not pressure tested like SAAMI munitions.
Pressure is the main difference that differentiates the .223 Remington from the 5.56 NATO. The chamber of the .223 Wylde was able to withstand the pressure of the 5.56 NATO cartridge, and the performance of the .223 cartridge was not as degraded as in the chamber of 5.56 NATO. It became extremely popular with shooters for its ability to fire 223 and 5.56 rounds and even the heavy 60 grain bullets used in shooting competition. As long as it is built to specifications using a good reamer and is in good general condition, the 223 Wylde chambers, originally designed by Bill Wilde, are also safe for use with both .223 Remington and 5.56×45 NATO ammunition.
For the same reason, all manufacturers that do not use Wylde .223 cameras use 5.56 camera sizes. This is because the 5.56 NATO and .223 Remington rifles have different chamber sizes. In particular, Remington .223 chambers are generally smaller and have a shorter inlet or free passage (the distance between the mouth of the case and the point where the rifling comes in contact with the bullet) at a steeper angle than 5.56mm chambers. Since, other things being equal, shorter strokes result in higher chamber pressures than longer strokes, this means that firing 5.56mm cartridges (which are already loaded at higher pressure) from the Remington .223 chamber can result in dangerous enlargement of the chamber. pressure.
In fact, not only is it safe to shoot 223 in the 223 chamber and 5.56 in the 5.56 chamber, but in these situations you will most likely get the best overall performance. Remember, we’re talking about .223 only chambered in 5.56, not 5.56 chambered in 5.56. Note that 5.56 cannot fire from chamber 223, but chamber 223 can fire from chamber 556 due to pressure differences. The 5.56 has a longer throat, which gives less pressure than the same cartridge chambered in .223.
Although the 223 can be chambered at 5.56, it will have a lower velocity due to the lower pressure. However, the lower powder capacity of the 223 bullet means that the 223 bullet has less power than the 5.56 bullet. External ballistic testing of the Model 223 using a standard 55 gram bullet exiting the barrel at 3215 fps shows that the 223 fps bullet speed drops by more than half the velocity at 500 yards.
In the .223 Remington rifle, the bullet creates chamber pressure in excess of 70,000 psi, which meets SAAMI (Sporting Weapons and Ammunition Manufacturing Institute) standards. The .223 Rem and 5.56 NATO maximum pressures of 55,000 and 62,000 psi, respectively, does not mean that ammunition will actually be loaded at that pressure. In practice, this means that you won’t be able to get the most out of real NATO 5.56 ammunition unless your rifle is built to NATO specifications such as lead, RPM and can handle slightly more chamber pressure.
However, given the general differences in cartridges and chambers, it is recommended not to use 5.56mm ammunition in firearms with a dedicated .223 chamber. In 1979, SAAMI warned that the 5.56 caliber chambers were different from the .223 sporting rifles, and that the use of 5.56 rounds in .223 rifles could increase the pressure to dangerous levels. Although the differences are small (~ 5% in the previously cited study), large 5.56 firing through the chamber of .223 can lead to overpressure malfunctions such as bursting primers or burnt cartridge heads and other firearm malfunctions.
If it is, it masks the difference in body and hardness of the primer. As has been pointed out many times, the main difference is not the camera, but the canyon. Also, the 5.56 military case is thicker, stiffer and has a slightly smaller capacity, which is usually too long for a .223 Rem Custom Match-Grade. Since both are cartridges, the main problem with these differences is when firing the 5.56 NATO cartridge into a 223 Rem loaded rifle. The biggest problem with these differences comes when firing 5.56 NATO to 223 Rem.
Due to the throat difference between the two chambers, the 223 Rem cartridge may not perform optimally in NATO 5.56 firearms. The .223 Remington’s chamber size creates a tighter fit to the bullet and therefore creates more pressure despite firing bullets of the same size from the same case, with a slightly warmer powder charge as more gas is released with the larger lead. This 5.56 NATO chamber size is actually slightly larger than the .223 Rem chamber – so you have smoother feeding and ejection, even from dirty weapons, to best serve you as a weapon – but it’s a basic dimension that matters the most.
For those interested in lead, the distance between the muzzle of the cartridge and the point of contact of the rifling with the bullet is called. Hence the long-range or lead round, which fires from the chamber with a shorter lead, as in the case of NATO 5.56 rounds from the .223 Rem.
The dimensions of the chamber for shotguns chambered for two cartridges are also slightly different. In between are chambers designed to balance pressure and accuracy, as the 5.56 NATO chambers’ long free passage and throat dimensions are often accused of being less accurate than Remington .223 chambers.
While the 5.56mm and .223 cartridges are similar in appearance, they are not identical on the inside. As you can see in the photo below, .223 and 5.56 mm cartridges have almost the same outer dimensions of the case.
This means that most of the time you can load and fire .223 rounds from the 5.56mm chamber and vice versa. With a double bore length (0.050 for 5.56 NATO versus 0.025 for Remington 223), the 5.56 NATO chamber can safely accommodate slightly higher peak pressures and extended nose cone bullets.
Apart from this free barrel difference, the remaining increments may represent the higher reliability of the 5.56 and may offer some of the accuracy of a 5.56 cartridge rifle over other equivalent Remington 223 shotguns. As you can see in the video, this is the chamber size difference between the 223 Remington and the 5.56 NATO (click/click to enlarge) Yes, the 5.56 NATO chamber is “one thousandth larger here and there” – but mostly The difference is the free channel length. The most important difference between the .223 and 5.56 chambers is the throat (or lead) length of each chamber. Comparing NATO and SAAMI regulations, the advantage of the 5.56 chamber is almost double that of the 0.223 chamber (0.162″ to 0.085″ respectively).
If the 5.56 cartridge contacts the rifling prematurely, it can cause pressure fluctuations in the chamber (leading to malfunction and potential damage). Now, if you take a 5.56x45mm NATO bullet already charged to higher pressure and shoot it into a Remington .223 case, the bullet will hit the rifling first, causing the pressure to rise earlier. Then you will feel more intense pressure until a potentially dangerous situation arises. Conversely, it’s perfectly fine to fire a .223 Remington round (usually a lower pressure round) through a true 5.56x45mm chamber, since you have a bullet designed to shorten the buck in a longer buck chamber.
When you fire the .223 into the 5.56 NATO chamber, the optimum 55,000 psi will not be achieved, speed, thermal ballistics and performance will suffer. The difference that usually makes the .223 lower pressure is that it is governed by the SAAMI specification, which generally reduces bullet pressure in the market.