Now that I have your attention! This .223 debate started on another thread and I nearly got hunted down by men carrying pitchforks and torches - so I figured I'd make more friends by ticking off the 7.62x39 crowd at the same time as the .223 crowd! Please read it all before you attempt to lambaste me! This did start on antoher thread, so I already answer some responses in here! Start: Both of these rounds will lose their popularity and potentially fade away if the militaries that use them switch to a new round. Here's my reasoning: Both rounds were first designed as purpose-built, new generation, military rounds. Designed for select fire guns, and for military use. They were both successful! Why? Because, they were both controllable and allowed the user to fire on full auto controllably, unlike previous "battle rifle" select fire ammo. BUT! Go on any Ak vs Ar debate and you will hear supporters of either side point out the successes AND failures of each round. .223 is easy to obtain, relatively cheap, accurate, easy to control, easy to carry ammo... BUT it lacks power at long range, is not found outside of N.America, cannot penetrate cover. 7.62x39 is similar - designed for the same purpose as .223, it is powerful, also pretty easy to carry, controllable. It is Not as accurate, and does not perform well at long range, but it penetrates cover quite well. BOTH rounds are successful military rounds, but have deficiencies. They were first generation, purpose built rounds, and so, as technology improves they can be replaced! WHAT MIGHT REPLACE THEM? Currently the 6.8spc and 5.45x39 are both under development as potential replacements. They solve the issues of the former rounds and reflect the new needs of the military. If the militaries adopt those new rounds, or any other the support for the original .223/7.62x39 will drop off. The older ammo will become less available/more expensive. People in th emilitary will be trained on new platforms - and so buy accordingly, folk that refused to buy the old rounds may see the new ones as a good compromise, and they will likely function better than the older ones that they replaced - otherwise why would the military adopt them!? And so, when the military drops them, only the civilian market will buy those rounds. But why would they? .223 has some use as a varmint/deer round, but there are many competitors for that. 7.62x39 could be used for hunting, or as a carbine, but again - is it really better than other civilian ammo for that? BUT WAIT! what about older military rounds that got replaced and still exist? To those who say that .308 still exists, or .303 brit, 30.06, 30-30, etc, I remind you that those munitions were made at a time when hunting rounds and military rounds were one and the same! Older military guns were just converted hunting guns, and had ammo to match! When the military use of those rounds ceased, they reverted back to hunting use without a problem! Animals have not evolved much in the last 200 years, and so what was an effective hunting round then, is still effective today! .223 and 7.62x39 were never built on hunting/civilian use - they were designed for military use only - and so as the newer second gen military rounds come out, they will likely replace the older ones, which have no civilian use fallback. END SO! To sum up, the popularity of .223/7.62x39 is backed by military use. As new rounds are developed for military use, these will get replaced. The civilian market has little use for these rounds besides hunting (which is also supplied by other hunting rounds). Over time, platforms will be made only for the new rounds, and so the older ones will slowly die off, as they become more expensive, but less useful. This will not happen overnight - it will take years, possibly 100 years or more, but in time it may come to pass that we'll live in a world with no .223 or 7.62x39. Like how .22lr replaced .22 long - lr started out more expensive, but was the better round. As time passed people switched to .22lr, .22 long become rare - platforms stopped coming out in .22long - and it is on the verge of extinction. PS- I love and own both rounds! Please be gentle!