Okay let me go dig up that post i made on ballistics along time ago
A rifle round is designed to engage targets at range, so it is smaller and has alot more gunpowder in it. This makes the bullet traver at much higher speeds, also the bullet is longer and narrower which helps its maintain speed of distance because it cuts through the air. Rifle rounds when they hit their target slow down and are balanced to tumble end over end creating a large cavity, or are designed to fragment from the force of impact (read: slowing down really fast, or impulse ) again creating a large cavity. but if you shoot someone at very close range with a rifle you might get the effect of overpenetration, because the bullet still has most of its speed (and therby most of its force) at that close of a range, the bullet runs the risk of just going right through your target without fragmenting or tumbling, or even transfering much force, leaving a nice clean hole.
Now pistol rounds are for the most part designed to do shock damage. Pistol rounds being much larger and wider slow down alot quicker. When a pistol round enters your target it slows down, therby transfering its energy unto the target, doing alot of damage to internal tissue. since pistol rounds slow down alot quicker once they hit something they generate a larger "impulse" .
However since they slow down alot quicker in a body, they also do the same in the air (in part to both the lower amount of powder and the wider profile of the bullet) meaning at range they bleed off speed quickly and therefore have lesss energy to transfer to the target.
Which is why a bullet stopped by a vest actually creates a larger impulse then one that penetrates, the vest stops the bullet alot quicker then tissue. Which is why getting shot with a bullet proof vest still does alot of damage, just it does it externally which your body can handle alot better (however a trama plate can reduce this damage signifigantly by absorbing the force)
note that you can also can a similar over penetration effect when using AP rounds on an unarmored target
By the way the "shockwave" effect is held up by a few rogue firearms experts but is dismissed as crap by the majority
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2003-02-04, 09:25 PM
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