9mm
Point #1: “Stopping power” is not our first priority. The number one most important factor in choosing defensive ammunition (and a firearm to use it in) is reliability. Every time you pull the trigger, the gun should fire. If you load your gun with Super Bullets but the gun doesn’t go off when you need it to, the Super Bullets don’t do you much good.
Accuracy is important, but it should not be the primary factor in choosing defensive ammunition. Most defensive shootings occur within a range of seven yards, in conditions of reduced lighting, under extreme stress. You are not going to be focused on bulls-eye accuracy. Don’t get too wrapped up splitting hairs between a load shooting 1.50” groups as opposed to one which shoots 2.00” groups at twenty-five yards. The real difference between the two is meaningless.
Point #2: There is a difference between “stopping” and “killing.” If you are forced to use lethal force, it is almost certainly because you or someone else is threatened with imminent death or serious bodily harm. In a defensive shooting, the priority is to stop the attack immediately. Shooting someone in the leg might cause an infection which kills eventually, but that doesn’t save you from return fire.
So just because a certain round has a reputation for killing doesn’t tell you if it is effective at stopping an attack quickly. Quite a bit of the scientific research into bullet wounds focuses on killing power, not stopping power.
Most modern defensive ammunition is some variety of JHP (jacketed hollow point). A JHP bullet has a hollow cavity facing forward. When the bullet strikes something, the hollow point tends to open up into a mushroom shape. This has two primary effects.
First, the bullet diameter is now wider, meaning the bullet cuts a bigger hole. It does more damage and has a greater chance of hitting a vital organ. Second, the wider contact surface meets greater resistance as it tries to push through, so it will not penetrate as deep.
If you are choosing ammunition, remember this: always choose JHP ammunition. Every major law enforcement agency in the country uses some form of JHP ammunition. Every major ammunition manufacturer touts its premiere JHP as the best defensive load.
Three numbers define a particular load. The first is caliber, which is a rough description of a bullet’s diameter. Don’t get too wrapped up on this. For example, a 357SIG bullet is actually 0.355” in diameter (which happens to be the same as 9x19mm). However, a .357 Magnum is actually 0.357” in diameter … and so is a .38 Special! But bullet diameter is one measure of a particular load.
The second is bullet weight. Bullet weight is measured in grains. One grain is equal to 1/7000 of a pound. So a light 115gr 9x19mm bullet (which is 0.355” in diameter) weighs about one quarter of an ounce; a heavy 230gr .45 ACP bullet (which is actually 0.45” in diameter) weighs half an ounce.
The third number is muzzle velocity. Muzzle velocity is simply the speed of the bullet as it leaves the muzzle, measured in feet per second. A fast 115gr 9x19mm load might be moving 1,350fps, while a slow 230gr .45 ACP load will probably rate about 850fps.
Another important number is muzzle energy. “Energy” in physics terms is the ability to do work. More energy means potentially more work. Muzzle energy is determined by plugging the bullet weight and muzzle velocity into a formula. Muzzle energy is measured in foot-pounds. Our 115gr 9x19mm bullet moving at 1,350fps has 465 foot-pounds of energy; the 230gr .45 ACP bullet moving 850fps has 369 foot-pounds of energy.
When that JHP strikes a fluid medium (such as the inside of a human body), it expands. The size of the expanded bullet, and the depth of penetration, are also numbers most people consider very important. These numbers are usually determined by shooting special, calibrated ordnance gelatin (jokingly referred to as “jello”).
Expanded diameter is measured in two ways. The most common is a raw measurement (e.g., 0.65”). The less common is as a percentage of the original caliber. So if a .40 S&W bullet (which is 0.40” in diameter) expands to 0.65”, you have 62.5% expansion.
Penetration is simply the depth, in inches, that a bullet moves through the target.
A lot of factors affect expansion and penetration. Bullet design is the most important. Bullet weight and speed also play a role (as a general rule, the faster the bullet is going, the more it will expand and the less it will penetrate).
Two other numbers are produced in gelatin testing. One is the permanent wound channel (the volume of the hole created by the physical path of the bullet). The other is the temporary stretch cavity (the volume of space which is temporarily displaced by the shockwave of the bullet moving through a fluid medium).
So what makes one load better than another? There are two thoughts on the subject.
One thought believes that light, fast bullets with high muzzle energy are best. These tend to produce higher temporary stretch cavities. The theory is that such bullets create more disruption inside the target and lead to more rapid incapacitation. These bullets tend to expand more (or even fragment), and therefore have less penetration than slower, heavier bullets.
The other thought tends to favor slow, heavy bullets … usually in larger calibers such as .40 S&W and .45 ACP. The bullets tend to penetrate deeply and cause longer (wider and deeper) wound channels. The theory is that such bullets are more likely to strike a vital organ because they are more capable of passing through intervening barriers as well as protective tissues such as bone.
These are very broad generalizations, of course, and a lot of people fall somewhere in the middle. Nevertheless, they define two different approaches to choosing defensive ammunition. Not surprisingly, in most calibers there are three popular bullet weights … a light fast bullet weight, a slow heavy bullet weight, and a middle ground.
Ammunition choice plays a much smaller role in stopping an attacker than shot placement.
Shot placement simply means putting the bullet(s) where the most damage will be done to the attacker. The primary target is what we call the thoracic triangle. The points of the triangle are the throat and two nipples. Shots to this area tend to make people FDGB (“fall down go boom”). Shots outside this area tend to have less immediate effects. Within reason, this is true regardless of caliber, ammunition, etc.
Almost any popular defensive JHP load (Gold Dot, Hyrda-Shok, SXT, Golden Saber, etc.) in a major caliber will be effective if shot placement is good. More importantly, if shot placement is bad, a “more powerful” round won’t do you any good.
In certain calibers, some defensive ammunition is labeled “+p” or “+p+” … this indicates that the ammunition is loaded to a higher operating pressure than standard ammunition in that caliber. Such “+p” ammunition is available in .38 Special, 9x19mm, and .45 ACP. There is no such thing as “+p” .40 S&W ammunition, even though some companies advertise their ammo as such. As a general rule, use +p loads for .38 Special and 9x19mm, but not in .45 ACP.
For bullet weight and muzzle velocity, it really depends on which caliber you are shooting. Smaller calibers (like .380 ACP, 9x19mm, and 357SIG) tend to work better with lighter, faster rounds. Larger calibers (.40 S&W and .45 ACP) tend to work better with heavier, slower rounds.
Shot placement … just keep thinking shot placement.
Point #1: “Stopping power” is not our first priority. The number one most important factor in choosing defensive ammunition (and a firearm to use it in) is reliability. Every time you pull the trigger, the gun should fire. If you load your gun with Super Bullets but the gun doesn’t go off when you need it to, the Super Bullets don’t do you much good.
Accuracy is important, but it should not be the primary factor in choosing defensive ammunition. Most defensive shootings occur within a range of seven yards, in conditions of reduced lighting, under extreme stress. You are not going to be focused on bulls-eye accuracy. Don’t get too wrapped up splitting hairs between a load shooting 1.50” groups as opposed to one which shoots 2.00” groups at twenty-five yards. The real difference between the two is meaningless.
Point #2: There is a difference between “stopping” and “killing.” If you are forced to use lethal force, it is almost certainly because you or someone else is threatened with imminent death or serious bodily harm. In a defensive shooting, the priority is to stop the attack immediately. Shooting someone in the leg might cause an infection which kills eventually, but that doesn’t save you from return fire.
So just because a certain round has a reputation for killing doesn’t tell you if it is effective at stopping an attack quickly. Quite a bit of the scientific research into bullet wounds focuses on killing power, not stopping power.
Most modern defensive ammunition is some variety of JHP (jacketed hollow point). A JHP bullet has a hollow cavity facing forward. When the bullet strikes something, the hollow point tends to open up into a mushroom shape. This has two primary effects.
First, the bullet diameter is now wider, meaning the bullet cuts a bigger hole. It does more damage and has a greater chance of hitting a vital organ. Second, the wider contact surface meets greater resistance as it tries to push through, so it will not penetrate as deep.
If you are choosing ammunition, remember this: always choose JHP ammunition. Every major law enforcement agency in the country uses some form of JHP ammunition. Every major ammunition manufacturer touts its premiere JHP as the best defensive load.
Three numbers define a particular load. The first is caliber, which is a rough description of a bullet’s diameter. Don’t get too wrapped up on this. For example, a 357SIG bullet is actually 0.355” in diameter (which happens to be the same as 9x19mm). However, a .357 Magnum is actually 0.357” in diameter … and so is a .38 Special! But bullet diameter is one measure of a particular load.
The second is bullet weight. Bullet weight is measured in grains. One grain is equal to 1/7000 of a pound. So a light 115gr 9x19mm bullet (which is 0.355” in diameter) weighs about one quarter of an ounce; a heavy 230gr .45 ACP bullet (which is actually 0.45” in diameter) weighs half an ounce.
The third number is muzzle velocity. Muzzle velocity is simply the speed of the bullet as it leaves the muzzle, measured in feet per second. A fast 115gr 9x19mm load might be moving 1,350fps, while a slow 230gr .45 ACP load will probably rate about 850fps.
Another important number is muzzle energy. “Energy” in physics terms is the ability to do work. More energy means potentially more work. Muzzle energy is determined by plugging the bullet weight and muzzle velocity into a formula. Muzzle energy is measured in foot-pounds. Our 115gr 9x19mm bullet moving at 1,350fps has 465 foot-pounds of energy; the 230gr .45 ACP bullet moving 850fps has 369 foot-pounds of energy.
When that JHP strikes a fluid medium (such as the inside of a human body), it expands. The size of the expanded bullet, and the depth of penetration, are also numbers most people consider very important. These numbers are usually determined by shooting special, calibrated ordnance gelatin (jokingly referred to as “jello”).
Expanded diameter is measured in two ways. The most common is a raw measurement (e.g., 0.65”). The less common is as a percentage of the original caliber. So if a .40 S&W bullet (which is 0.40” in diameter) expands to 0.65”, you have 62.5% expansion.
Penetration is simply the depth, in inches, that a bullet moves through the target.
A lot of factors affect expansion and penetration. Bullet design is the most important. Bullet weight and speed also play a role (as a general rule, the faster the bullet is going, the more it will expand and the less it will penetrate).
Two other numbers are produced in gelatin testing. One is the permanent wound channel (the volume of the hole created by the physical path of the bullet). The other is the temporary stretch cavity (the volume of space which is temporarily displaced by the shockwave of the bullet moving through a fluid medium).
So what makes one load better than another? There are two thoughts on the subject.
One thought believes that light, fast bullets with high muzzle energy are best. These tend to produce higher temporary stretch cavities. The theory is that such bullets create more disruption inside the target and lead to more rapid incapacitation. These bullets tend to expand more (or even fragment), and therefore have less penetration than slower, heavier bullets.
The other thought tends to favor slow, heavy bullets … usually in larger calibers such as .40 S&W and .45 ACP. The bullets tend to penetrate deeply and cause longer (wider and deeper) wound channels. The theory is that such bullets are more likely to strike a vital organ because they are more capable of passing through intervening barriers as well as protective tissues such as bone.
These are very broad generalizations, of course, and a lot of people fall somewhere in the middle. Nevertheless, they define two different approaches to choosing defensive ammunition. Not surprisingly, in most calibers there are three popular bullet weights … a light fast bullet weight, a slow heavy bullet weight, and a middle ground.
Ammunition choice plays a much smaller role in stopping an attacker than shot placement.
Shot placement simply means putting the bullet(s) where the most damage will be done to the attacker. The primary target is what we call the thoracic triangle. The points of the triangle are the throat and two nipples. Shots to this area tend to make people FDGB (“fall down go boom”). Shots outside this area tend to have less immediate effects. Within reason, this is true regardless of caliber, ammunition, etc.
Almost any popular defensive JHP load (Gold Dot, Hyrda-Shok, SXT, Golden Saber, etc.) in a major caliber will be effective if shot placement is good. More importantly, if shot placement is bad, a “more powerful” round won’t do you any good.
In certain calibers, some defensive ammunition is labeled “+p” or “+p+” … this indicates that the ammunition is loaded to a higher operating pressure than standard ammunition in that caliber. Such “+p” ammunition is available in .38 Special, 9x19mm, and .45 ACP. There is no such thing as “+p” .40 S&W ammunition, even though some companies advertise their ammo as such. As a general rule, use +p loads for .38 Special and 9x19mm, but not in .45 ACP.
For bullet weight and muzzle velocity, it really depends on which caliber you are shooting. Smaller calibers (like .380 ACP, 9x19mm, and 357SIG) tend to work better with lighter, faster rounds. Larger calibers (.40 S&W and .45 ACP) tend to work better with heavier, slower rounds.
Shot placement … just keep thinking shot placement.
