Man, a bullet is a bullet. When you get up into the .30 calibers when you hit what you are shooting at you are going to blow the crap out of it. I know, from personal experience that a .30-06, which happens to be VERY ballistically similar to the 7.62x51 NATO, can punch through damn near a third of an inch of solid steel plate at 300+ yards with EASE. And I was using 150 grain remington boat-tail rounds, which is the standard.
I am not so sure about the performance specifications of the 7.62x54 Russian round, but you could probably say with confidence that it and the two rounds I mentioned above would all have VERY similar performance. Especially in penetration of steel and wood etc, but when it comes to accuracy I happen to know that the 7.62x51 NATO is very accurate out to 450+ yards, and depending on who you ask is a 'little bit' more accurate than the .30-06 7.62x63. We are talking inches out to about 600 yards, and then these bullets begin to drop ALOT, and unless you are a super trained sniper with an Uber sniper rifle, scope, spotting scope etc, you are not going to be able to hit anything delibrately. I am sure that this is true when it comes to the Russian round aswell, but I really wouldn't expect it to be any better than the 762x51 NATO. Because from what I have heard, the Ruskies haven't always been known for their quality of ammunition, 7.62x39 casings are made of tin to reduce cost, but I don't know if it is the same case with all Russian ammunition.
As for the 5.8x42 Chinese versus the 5.56x45 NATO versus the 5.45x39 Russian, it is probably the same case of similarity. Because what the manufacturers of all of these bullets were trying to achieve was basically the same thing; smaller, lighter rounds makes it easier to carry and cheaper to mass produce, but still kill people. If you ask me these smaller rounds are inferior, and that is the same opinion of some of the SF guys that are in country right now. That is why they are considering replacing the 5.56x45NATO here in the U.S. If it is replaced, it will probably be replaced with something similar to the 6.8x43 remington, which has the accuracy of the lighter rounds out to 500 yrds, but the knockdown power of the heavier rounds, which is exactly what the SF guys are looking for. I think that it would be a better combat round than the smaller rounds, coming from someone who has never been in combat before. But I have shot plenty of pretty much all of the rounds mentioned above except 5.8mm Chinese, 5.45x39 USSR, 7.62X51 NATO, and 7.62x54 USSR.
Well, theres my 2 cents
