This should answer your question you had about .2223 and 5.56 rounds and AR vs AK: Which is Better? http://thearmsguide.com/645/is-there-a-difference-between-223-and-5-56/ Is There a Difference Between .223 and 5.56 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. Which should you choose? As with so many elements of making a firearm purchase, the “right” option is subjective. If all you intend to purchase are .223 Remington rounds, There is nothing wrong with getting a rifle chambered for .223. However, if you want the option of firing milspec 5.56 through your rifle, you may prefer Picking up a 5.56 chambered rifle. After all, you can still fire the .223 through it, safely, if you want. Price and personal preference are also factors to Consider when making that decision. What works for you? ------------------------------------------------------------- AR vs AK: Which is Better? Published on June 26th, 2014 | by Destinee (FateofDestinee) Submit to reddit 1 One of the fiercest, and longest running, debates within the firearms community is this: which is the better “battle rifle:” the AR or the AK. The topic has been done to death, so I thought I’d feature the two rifles in a different setting: working together. The video embedded above features an AR-15 and an AK-74. The featured AR, like many rifles of its type, is a custom build. Some of the key components included are a DI Daniel Defense DDM4V7LW upper, a LMT Defender lower receiver, and Troy flip up battle sights. On the other end of the spectrum, the AK74 I’m wielding above is a standard milsurp rifle. This Romanian SAR-2 is in the same condition now as when I first cleaned off the cosmoline, except, well, dirtier. Some argue that the AK-74’s 5.45×39 cartridge is the Eastern European answer to the AR-15’s 5.56×45 NATO round. On the range, I’ve found the perceived recoil to be similar, but let’s look at some measurable data. The AR’s 5.56×45 has a standard muzzle velocity of about 3,100 FPS, compared to the AK-47’s 7.62×39’s average muzzle velocity of about 2,300 FPS. The AK-74’s 5.45×39 round flies between the two at about 2,900 FPS. What is my preference? Both. I think the AR-15 and AK-74 each have their merits and demerits. I enjoy the remarkable volume of options for customizing AR style rifles. Between uppers, lowers, barrels, triggers, grips, stocks, hand guards, muzzle devices and more, there are countless options for completely unique AR builds. Although, these kinds of rifle builds have a way of running off with your wallet. Military surplus firearms, like my AK-74, are often acquired for considerably less coin. The AK-74 in this video cost about one third the overall price of the AR-15 firing next to it. It also bears mentioning how reliably my AKs have performed on the range, as compared to my AR style rifles. Over the years, AKs have established a reputation of being nigh impossible to impede their ability to fire. Thousands of rounds of carbon fouling? Mud? Sand? Ham sandwich? No problem. The AK-74, like its big brother AK-47, will take all kinds of abuse and keep on kicking. When it comes down to it, the “better” rifle is really a matter of personal preference. Which is your favorite?