(GunAuction.com) — Online retailer Cheaper Than Dirt recently posted an extended discussion entitled “The Myth of Handgun Stopping Power” in the company’s Shooter’s Log. Technical writer “CTD Mike” wrote, “When it comes to ammunition selection for personal defense, we need to separate real from hype before making a purchase. If you make a bad purchase on a vacuum or a home gym, you are likely to be a bit embarrassed. Making a bad purchase on defensive ammunition could have dire consequences. Let’s talk about some fundamentals so you’ll be able to make an informed decision.”
Four terms need defining for us to understand how bullets work.
Penetration is the amount of tissue—bone, fat, and muscle—that a bullet passes through.
The permanent cavity is the amount of empty space—the hole—left in the body behind the bullet.
The temporary cavity is the momentary expansion of the permanent cavity stretching as the bullet’s kinetic energy is transferred to it.
Fragmentation is the separation of the bullet into smaller chunks, or pieces, which leave the permanent cavity and spin off in different directions.
Regardless of velocity, the bullet crushes the tissue in front of it as it penetrates or tunnels through that tissue. After the infamous “Miami Firefight”of 1986, the FBI set a minimum penetration requirement of 12 inches for their ammunition. This became the industry standard. All bullets penetrate and leave behind a measurable permanent cavity, even the .22 LR. All bullets also create a temporary cavity, although actually measuring it is nearly impossible. Fragmentation is dependent on two factors; bullet design and velocity. Impact velocities above 2,000 feet per second can cause fragmentation in full metal jacket bullets with thin jacketing, such as M193 5.56 NATO. Soft point or hollowpoint rounds may also fragment at the same velocities.
In rifle rounds, fragmentation accounts for a lot of the bullet’s ability to destroy tissue and stop bad guys in their tracks. Making slower pistol rounds fragment requires specialized bullet designs that fragment very easily. The problem with these rounds, such as the Glaser Safety Slug, is that they fragment immediately without penetrating. They are advertised as being safer to shoot indoors because they won’t penetrate walls and kill innocents on the other side. This is true! However, a round that can’t penetrate two layers of brittle sheetrock isn’t going to devastate a 250-pound man coming at you with a crowbar either. It will break up immediately upon hitting his skin, shower the first few inches of fat and muscle with little specks of lead, and fail to reach his vital organs. This is not what we want. At this time there is no magic pistol round that is safe when you miss, but “knows” when it hits a bad guy and decides that now is the time to penetrate and then fragment. Any round capable of penetrating tissue to FBI minimum standards is also capable of penetrating doors and walls. Fragmentation in pistol rounds falls into just two categories, won’t happen and fragments without penetrating.