KP wrote:
A 7.62 will do more damage IRL than a 5.56. So it does in PR. Bullet damage IRL also depends on distance, bullet velocity, the type of round (FMJ, JHP, etc.) used and many more factors.
This point is highly debateable. I refer you to these diagrams if the bullet's wound profiles:
http://matrix.dumpshock.com/raygun/basics/pmrb.html
Firstly, despite their small size, 5.56mm bullets traveling at the proper speed fragment inside the target's body, almost like a tiny hand grenade, shredding tissue, creating a permanent cavity much greater than any other military rifle bullet short of 0.50 BMG, and requiring extensive treatment to any (unlikely) survivor.
7.62mm bullets (whether 7.62x51 or 7.62x39) create a larger temporary cavity, but this is done by stretching the tissue and not by crushing/severing it. The stretching action only has major effect on solid (as opposed to hollow) organs and allows the tissue to return to it's previous untouched state in a week or two without any surgical treatment (as opposed to 5.56mm which requires removal of the bullet and all of it's individual fragments).
Furthermore, this large temporary cavity is caused by a yawing action (aka tumbling) which happens very late in 7.62 bullets compaired to 5.56mm and 5.45mm. Thus, the yawing action can often occur after the bullet has allready passed the major organs, or the bullet can exit the body completely before yawing...delivering little if any of that large temporary cavity and instead leaving a wound comparable to that of a small handgun bullet (ie 9mm or 7.62x25 tokarev).
The catch is that 5.56mm only fragments when hitting the target beyond 2600-2700 fps...otherwise it doesn't yaw or fragment; it just goes straight through like .22 magnum. When fired out of a full-length rifle (ie M16A2) the proper velocity to fragment will be sustained out to 150 meters, which is enough for most small arms engagements. However, out of short barrels the range gets significantly less; 100 meters for a 16" barrel (L119A1) and only 50 meters for a 14" barrel (M4A1).
Additionally, the proper velocity to fragment may be lost when penetrating any materials before hitting the target, from walls to body armor. Since many modern combat units use body armor, this sounds like a strike against 5.56m, but remember that 7.62x39mm (AK-47 type) doesn't even penetrate most body armor.
So in conclusion, it's not really as clear cut as most make it out to be. The common "7.62 is bigger so it has more knockdown power" mentality is just plain ignorant. Against unarmored targets, 5.56mm and 5.45mm do equal or superior damage to their 7.62mm counterparts. Against armored targets, 7.62x51 is better than 5.56mm, but 7.62x39mm is worst. 5.56mm damage is undependable at longer ranges, but most small arms combat happens inside of 100 meters or less, so this often negligible.
Bloody Hell! Literally!
