>>64153438
>>64150811
It always bear repeating that energy is never the full story.
5.45x39mm has the same 1000ft/lbs as .30 U.S Carbine, and these ft/lbs can also be matched by 10mm Auto in a pistol when loaded with a VERY lightweight 77gr bullet, but you're looking at successively shorter effective range and weaker terminal ballistics with each of these, they are so very different from each other in all other characteristics. As saucy as you can load a pistol in 10mm Auto, it's never going to be able do what a 7n6 load of 5.45x39mm can do, 180gr and heavier being much better suited bullet weights for the vaunted "Centimeter" anyway.
While one can discuss in detail whether 5.56x45mm or 5.45x39mm is superior, I would say that both are more than adequate and have worked out tremendously well, with nil recoil, flat trajectory, light ammo, and goatse wound characteristics. Both are a .22ish caliber cartridge of similar weights which are more powerful than .22 Spitfire, which was Melvin Johnson aiming to take the M1 and M2 Carbines into the future as budget SCHV guns by necking down .30 U.S Carbine to .22 caliber.
