Originally posted by: IGBT
Originally posted by: TallBill
Originally posted by: IGBT
..search your conscience for your own answers on what you know or don't know. Credible fire arm instructors know as sectional density increases in a projectile the difficulty of mastering proficiency increases which is why police are required to "qualify" annually or semi annually with their service weapon.
Stop being a retard. If you have any firearm for home defense it is your responsibility to practice with it every so often as well, whether it be chambered in 22LR or 458 socom.
Btw, you are extra retarded for using "sectional density". I've met plenty of "credible firearm instructors" and not one of them has ever said that. Stop talking out of your ass.
..I know your in the military and you do what your told based on your training. So I guess they felt certain aspects of ballistics weren't important for you to know or it's just over your head and they didn't want to confuse you:
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Sectional Density
One of the most important factors is determining the degree to which air resistance will affect a projectile is cross-sectional density. One can think of cross-sectional density as a measure of the carrying power of a projectile. For example, if you throw a ping-pong ball through the air, it will experience some air resistance proportional to the cross-sectional area of the ball that comes in contact with the air. The ping-pong ball, which has a small mass, is likely to be affected a great deal by the air resistance it experiences as it travels. An equally sized lead ball thrown through the air experiences an effectively non-existent air resistance, due to the ratio of the lead ball's mass to its cross-sectional area, which is much greater than the ping-pong ball's. It is very important when considering the performance of a projectile to keep in mind the properties of cross-sectional density (Heard, 84).
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..I'll bet this is news to you too:
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Ballistic Coefficient
To put a quantitative value on the degree that air resistance affects a certain type of bullet, engineers developed the ballistic coefficient:
C= w / (i x d^2)
where C= ballistic coefficient, W= weight of bullet, i= form factor, and d= diameter of the bullet.
Simply put, the form factor corresponds to the shape of the bullet and is inversely proportional to the degree of aerodynamic characteristic of the bullet, i.e. a pointy bullet has a higher number and a flat one has a lower number (Heard, 84).
By revealing the degree to which a bullet will retain its velocity, the ballistic coefficient can indicate the amount of drop of the bullet, and therefore its resulting accuracy. Although it is possible to design bullets with very high ballistic coefficients, this can be both beneficial and detrimental to bullet performance in terminal ballistics.
Terminal Ballistics
When studying terminal ballistics, engineers and scientists are interested in determining the effects of a projectile on a target. The important factors to consider are energy, penetration, and expansion.
Energy
Ironically, the same energy that we are trying to minimize in the recoil found in internal ballistics should be maximized in terminal ballistics. The idea is for the bullet to hit the target with as much energy as possible. Recall the equation for kinetic energy:
K= 1/2 mv^2
This indicates that the higher a projectile's velocity upon hitting a target, the more energy is carried into the target, thus causing more damage.
In the real world, energy is conserved, whereas in the movies it can be created out of thin air. Recall that the kinetic energy released when a bullet hits a target is less than the kinetic energy that the gun imparts on the bullet when it is fired - this is a necessary consequence of air resistance and the associated decrease in velocity. That means that if a bullet were to knock a bad guy off the ground and through a window, it would probably break the shooter's shoulder while sending him flying backwards.
Penetration
Equally important to the energy carried by a bullet is the amount of penetration that can be achieved when it hits a target. African big game hunters will tell you that it is vitally important for bullet to be able to penetrate a target because energy alone cannot take down a large animal. After all, an elephant can absorb much more energy as a result of being hit with a bullet than a shooter can through recoil. A bullet can do no damage to a target if it cannot penetrate the armor.
To remedy this, engineers developed a couple good solutions, most obvious of which simply makes the bullet sharper. Indeed, this is a very good solution because it also makes the ballistic coefficient higher, resulting in all the benefits of increased velocity. Another option is to make bullets harder. A hard bullet will penetrate without breaking into small pieces that are more easily slowed down.
Unfortunately, bullets that penetrate too well also tend to pass through objects without causing much damage. A gun that just makes neat little holes is only useful for target practice; what is needed is a controlled way for a bullet to penetrate an object and then release all of its energy inside.
Expansion
The solution to this dilemma is expansion - we want our highly aerodynamic bullet to enter the target and deform. The deformation will cause the ballistic coefficient of the bullet to decrease, thus transferring the energy of the bullet to the target. In an ideal situation, the bullet penetrates the target to a desired distance and stops. Engineers have created a plethora of different types of bullets with different terminal characteristics for different applications.
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