5.56x45mm NATO 7x43mm EM-2 7.6x39mm M43 7.62x51mm NATO
bullet weight 4.01 g (62 gr) 9.08 g (140 gr) 7.9 g (122 gr) 9.72 g (150 gr)
bullet velocity, at muzzle 921 m/s 745 m/s 710 m/s 860 m/s
bullet velocity, at 300 yards (273 meters) 585 m/s 570 m/s 470 m/s 674 m/s
bullet velocity, at 550 yards (500 meters) 385 m/s 450 m/s 341 m/s 516 m/s
bullet energy, at muzzle 1700 J 2519 J 1991 J 3594 J
bullet energy, at 300 yards (273 meters) 686 J 1475 J 872 J 2207 J
bullet energy, at 550 yards (500 meters) 297 J 919 J 460 J 1294 J
5.56 weighs 12g and 7.62x51 weighs 24. The person with the 5.56 fires with 3 round burst, the person with the 7.62 fires semi-auto. 3 shots=1 kill or 1 shot = 1 kill? Which is better? 36g or 24g? A 30 round 5.56 will get you ten pulls of the trigger if set on 3 round burst (the 3 round burst compensates for the smallness of the round. A 20 round 7.62 will give you 20 pulls.
