sighting in on: Understanding Bullet Performance
ability to instantly incapacitate a suspect. It will take anywhere from 10-15 seconds or longer, de- pending on what part of the body is hit. T e depth that the bullet penetrates is ab-
solutely critical in reaching vital organs. T at depth can vary depending on the angle that the bullet enters the body. A few inches through the sternum or over 12 inches for a round that enters the arm, traverses through the rib cage, lungs and heart of a large subject. T e FBI Pro- tocol requires that bullets penetrate to a depth of 12-18 inches in gelatin to demonstrate ad- equate penetration in a shooting.
Penetration is determined by bullet mass and design, NOT by velocity. T is came as a surprise to me. Boden explained that as velocity increases, the bullet will open sooner, slowing it down and in many cases causing the higher velocity round to penetrate less deeply. So a +P or +P+ round may give shallower penetration along with more recoil than a standard velocity round.
Speed Kills T e speed that a bullet travels CAN be impor- tant. Rifl e rounds traveling over about 2,200 feet per second (fps) attain hydrostatic shock, which increases and disperses a shock wave through the body since it consists mostly of water. T is means that the bullet can cause additional dam- age to other organs along the bullet path. However, if the speed is below 2200 fps, the damage will be limited to the wound channel caused by the bullet. Handgun rounds run be- tween 850-1400 fps. I’ve already mentioned the eff ect or lack
of eff ect that +P and +P+ rounds can have on penetration. T e Mark Coates shooting showed us a perfect example of lack of pen- etration killing power. During that incident, Trooper Mark Coates shot a suspect fi ve times at a close distance. All of the rounds from his .357 revolver failed to reach the vital organs of an obese killer. Coates was shot several times by a .22 mini revolver. Unfortunately, not all of the rounds struck his vest. One hit his left upper arm, turned and followed the bone into the chest cavity, and he died on scene. T e sus- pect survived to stand trial.
Carrying a submachine gun in your squad?
T e rounds in your gun may have been tested in a pistol according the FBI or Border Patrol testing protocol and proved adequate to the task. Put that same round into a sub gun with a longer barrel, which will result in higher ve- locity, and the results may change dramatically. T e bullet designed to expand and penetrate adequately at pistol speed may now break up
on impact and/or lose penetration, potentially resulting in a failure like the Coates shooting. If you’re carrying a sub gun, has the ammo been tested at those velocities?
Physics Are Scientifi c Laws; You Can’t Break Them
Repeat after me, knockdown power does not exist! Newton’s law tells us that for every ac- tion there is an equal and opposite reaction. Forget Hollywood and TV because bad guys won’t fl y backward due to bullet impact. Johan gave the example whereby a 9mm has the impact of a 10-pound weight dropped from a height of ¾-inch. A .45 ACP has the impact of a whopping 1.1 inches. As velocity increases, so does recoil. How is
your recoil control with your weapon? When you shoot your fi rearm are you controlling the weapon? When you shoot your pistol, does the slide come straight back and then go forward with no lift in the muzzle? Or do you have to force the muzzle back into sight alignment be- tween each shot? As a fi rearms instructor, I would make several suggestions on how to control the gun. Make sure both of your arms are straight. T is keeps the el- bows from fl exing and causing rise. A fi rm grip and locked wrists contribute to hanging on to the gun with as much of your hand on the grip as you can get. Recoil will move in the direction of least resistance. If there is a gap in your grip, then that is the direction the recoil will go. When you shoot one handed with your strong hand, the gun lifts up and to the left, demonstrating physics in mo- tion. Any bent joint, such as your wrist or elbow, will allow a recoil leak and can cause a malfunction if the semi-automatic pistol isn’t held in place. Bring the gun out toward the target at shoul-
der level and lower your head to the gun. When the gun is above shoulder level, the angle acts like a lever and causes the gun to rise. Straight arms that lead directly back into the torso allow the recoil to travel directly into the body. T at mass is greater than the recoil of the pistol and it allows the rearward impulse to be dispersed by it. Dropping your head down and forward takes a 20-pound weight and brings it into the game just like the body, reducing felt recoil. Leaning forward slightly brings the torso in play to take up recoil even more. Watching Johan shoot into the ballistic gel reconfi rmed these shooting ba- sics. Even though he was only fi ring one round at a time, his years of training and recoil control were evident every time he pressed the trigger. Why is recoil control critical control? In gunfi ghts, cops fi re around 5-8 rounds per
second according to the research conducted by the Force Science Institute. If you’re shoot- ing that fast and your muzzle is lifting each time, then where will your second, third, and subsequent shots be going? When you train, do you shoot slowly for score? If you are training for a gunfi ght, you better pick up the pace and practice at combat speeds of around fi ve rounds per second or more. You may be in for an unpleasant surprise on the street if you practice too slowly.
Boden further explained that recoil is mea- sured in Kinetic Joules (kj). He explained the diff erence in recoil between a .40 and a .45. Both of them have 35 kj of recoil. T e dif- ference is the .40 releases that energy in 2/10 of a second and the .45 in 4/10 of a second. He explained that is why the .40 has a much sharper recoil snap while the .45 has more of a push, making it easier to control.
Big Bullets Make Big Holes Unless you make a Central Nervous System hit, which will result in an instant stop, the bad guy will have to collapse from loss of blood. Bigger holes drain liquid faster and that is one of the purposes of a bullet that ex- pands, to create a bigger hole.
Boden explained that the FBI protocol required bullets to expand to 1.5 times their original diameter. He gave the following in- formation as examples of caliber designation, actual bullet diameter, and expansion after FBI protocol fi ring:
CALIBER
9 mm .355 .357 .40 .45
.355 .400 .451
DIAMETER EXPANSION .532 .532 .600 .676
You will notice there isn’t a whole lot of
diff erence between the calibers, especially the 9 mm, .357, and .40. Johan then posed the question that if the expansion is basically iden- tical and the penetration is about the same, then what is the benefi t of a weapon that has more recoil like the .357 Magnum and .40 S&W? He also noted the increased wear and tear on the gun because of the high velocity and the increased cost of ammunition. Based on Boden’s expertise, the .45 is recom- mended for those shooters who are comfortable with a gun that has a larger frame and a smaller round capacity. T e 9mm is recommended for those who want higher capacity and a smaller frame size.
27 The Police Marksman May-Jun 2014
www.policemarksman.com
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