Sigh. Even a pundit with with his heart in the right place hasn't a clue about firearms. The AR-15, M16 and similar weapons all use the 5.56 cartridge, which is identical to the .223 Remington. It is a wimpy cartridge with a 40-60 grain projectile, a muzzle velocity on the order of 3000-3500fps, and a muzzle energy on the order of 1000-1300 foot pounds. The round used in the AK-47 and its clones is on the same order, with a heavier projectile of 120-150 grains, slightly slower at around 2300-2400fps and slightly more energetic at 1500-1800 foot pounds. Neither is anything special, and using these rounds for hunting big game, especially the 5.56/ .223, would be irresponsible.