» Tue May 17, 2011 12:17 am I didn't want to get into this...but it seems I have no choice...
Very well. Those who are sensitive, however, I strongly urge to skip this post. Some gruesome details will have to be explained.
Now, wounding with projectiles basically is the sum of two factors: PENETRATION and SIZE OF WOUND CAVITY.
Penetration is in turn a factor of bullet shape, mass, and velocity. Wound cavity depends partially on the diameter of the bullet, but mainly on whether the bullet expands in the body or not, and whether the bullet tumbles inside the body or not.
The ideal bullet for wounding, therefore, must be fast and heavy enough to penetrate deeply into the body, but not so fast and heavy that the only wound cavity left in the body is the tunnel track that the bullet leaves as it punches into the body and punches out the other side and then goes on its merry way towards the horizon. No, it should ideally enter the body deeply, then either expand inside the body or tumble AND REMAIN INSIDE THE BODY.
*This, BTW, is why all the armies of the world changed from the .308 type rifle rounds of WW2 (7.7 British .303, 7.92 German Mauser, 7.5 French Hotkiss, etc) to the smaller, deadlier 7.62 x 39 (ex-Warsaw Pact Standard) and the 5.56 x 45 (NATO and US Standard) bullets after WW2.*
Now, bullets which expand (Dum Dum Bullets, named after the Arsenal where the British first Manufactured them, in Dum Dum, India) have been outlawed by International Treaty since the 1920s. This of course has not prevented rogue shooters from deliberately making expanding bullets, the most common way being the filing off of the tips of the bullets.
This is necessary since the metal jacket covering of modern bullets prevents them from expanding like the round lead balls of the musket era (This answers your point of the killing power of musket balls!).
For the layman, an excellent description of how an ordinary jacketed rifle bullet can be turned into an illegal dum dum bullet may be found in Frederick Forsyth's "the Day of the Jackal" novel. For a more detailed and technical explanations of how various designs for jacketed dum dums were conceived, the Jane's magazines are a good place. I also reccomend Anthony William's books and website, although his terminal ballistics explanations are a bit sketchy.
However most of the research since WW2 has focused on the 'legal' way of wounding, which is the 'fast tumbler' bullet. This is a bullet which is deliberately designed to be tail-heavy and to be stable only through high spin (which means that the barrel has to be rifled for a "fast" pitch) and which, therefore, will tumble, twist, bend, deform, and fragment inside the body after it has penentrated to a depth of ten inches or so. The russians in their latest 5.45 bullet achieved this by only partially filling the bullet with lead and leaving an air gap at the tip.
Now about the wounding effects of large bullets...
In WW2 and subsequent conflicts, Field Army Surgeons of all armies found that the easiest wounds to treat were those of soldiers whom had been hit by aircraft bullets of the .50 cal or even larger 20 mm. The heavy weight and high velocity of these bullets made for small, clean wounds that only needed stitches for the most part. There are many other factors in wounding, of course, such as whether the bullet had hit anything solid before hitting the soldier, but generally speaking, a clean shot by a heavy machine gun or cannon was a clean wound. Whereas a smaller bullet such as the 9mm bullet used in submachine guns made for a MUCH dirtier and nastier wound that would destroy more body tissue, and cause massive internal and external bleeding...
In Vietnam, US soldiers found that the best shot for the M-16 was between 5-15 meters, because the bullet was still unstable at so short a range. The tumble effect of the bullet was so huge that it was not at all unusual for entire limbs to be torn off by a single bullet strike.
Two bullets striking close together create a synegy that is greater than the sum of their seperate wounding paths.
Now, some points regarding sniping IRL.
As every experienced shooter knows, wind direction, wrong estimate of range, hand shaking, and even elevation above sea level and air temperature plays havoc with bullet aim, especially at ranges greater than 500 meters. This is why defensive snipers have already pre-zeroed various landmarks on a battlefield for range, so that when a target moves near that landmark the range is already calculated. Offensive snipers of course do not have that luxury.
For this reason snipers, especially offensive snipers, either set up a shot using not seconds but minutes in aiming and fine turning their shots...and they nearly always have an assistant to help calculate the range, wind sideslip, and the 101 other things that can ruin a shot. This is why snipers place in counterterrorist sniping are trained to shoot in SALVO - a snap shot by a sniper at long range will nearly always miss, which is why salvo fire is necessary. (You do not have the luxury of taking five minutes to set up a shot in counterrorism shooting!)
And it is that 'salvo fire' that I have tried to replicate, on a small scale, with my twin barrel.
Regarding Armor piercing...
The vanilla .308 will pierce today's body armour easily at a range of 200 meters, and has a greater than 50% chance up to 400 meters.
Of course, power armour will probably be better than today's kelvar...and that's the unknown. How much better? A good rule of thumb is that it takes an equal thickness of face hardened nickel steel armour plate to the diameter of the bullet to stop it...so 8 mm of armour plate should stop a .308 at 400 meters. However, at 100 meters all bets are off. And we are talking of vanilla bullets here, not the tungsten core armor piercing variety.
