When fired through angled glass, some bullets have a tendency to tumble but can still effectively incapacitate the intended target.
Today’s shooters have a choice of numerous highly capable defensive rounds, such as these Speer and Federal selections.
Winchester’s PDX1 ammunition, shown in a cutaway illustration in .357 SIG, uses a hollow point design that offers maximum expansion in tissue.
For self defense, you want a handgun round that both creates a large permanent wound cavity and does not overpenetrate and pass through a target.
On TV and in the movies, we often see people flying backwards after they have been shot. This is, of course, pure fantasy since the laws of Newtonian physics show that any gun powerful enough to do that would have the same effect on the shooter. Nevertheless in any self-defense situation, it is vitally important to understand what your ammo can and can’t do.
In the Spring of 1986 in Miami, eight FBI agents cornered two bank robbers, and the shootout that ensued sparked an intense debate and adjustment of how law enforcement officers were armed and trained nationwide. Early in the gun battle, one suspect was shot with a 9mm round that went through his arm and into his chest. The wound, the first of several, proved fatal, but not before he was able to kill two FBI agents and wound several more. The entire gun battle lasted less than five minutes with almost 150 rounds fired.
Following this tragic incident, the FBI spent considerable effort in studying wound ballistics and ammunition. How was it that, despite numerous wounds, the two suspects were able to continue fighting? What the FBI found in their study is that the only two things that stop a person quickly and decisively is damage caused by blood loss or immediate central nervous system trauma. The most important factors in this regard are shot placement, size of the wound cavity, and penetration.
Only Hits Count
Shot placement is a factor of accuracy that comes from practice, but bullet effectiveness is a function of its design. For personal protection and maximum effectiveness, the larger the permanent wound cavity the better, which is why expanding or hollow point ammunition is preferred. The FBI determined in their testing that at a minimum, a bullet must be able to penetrate at least 12 inches in ballistic gelatin (and up to 18 inches is preferable) in order to hit and damage vital organs and blood vessels.
Of course, over-penetration is undesirable in both a law enforcement and home defense situation. This is another advantage of expanding ammunition in that as it expands and creates a wider wound channel, the increased surface area of the bullet also helps to slow it down. Non-expanding ammunition can penetrate much farther and exit the target still continuing its lethal trajectory.
I attended a ballistics seminar hosted by ATK, the world’s largest producer of ammunition including Federal and CCI/Speer, with in-depth demonstrations of bullet performance through various barriers into ballistic gelatin. We all know that the force of the bullet is a factor of its mass or weight multiplied by its velocity. Velocity does have a higher multiplier effect on force, but faster bullets don’t necessarily perform better when it comes to penetration.
Adequate expansion and penetration are factors of bullet design and weight more than anything else. Ammunition that is rated +P will produce higher velocities and more force but will not necessarily penetrate better.
In terms of bullet design for expanding ammunition, one factor is shooting through heavy clothing. The fibers of the material, or even drywall, can clog the opening of some hollow point bullets, causing them to not expand and resulting in overpenetration. Also, some hollow point bullets may experience jacket separation when going through barriers. This fragmentation of the bullet divides its forward momentum among the individual fragments, slowing each down and possibly failing to deliver sufficient penetration for any of them to cause threat-ending damage.
In the demonstration, we tested various types of Federal ammunition through several layers of denim and through windshield glass, and then measured the expansion and penetration of each round. All the rounds performed extremely well and achieved expansion of 1.5 times their original diameter or greater. Through windshield glass, given that it is an angled surface, bullets had a tendency to tumble but they still expanded and penetrated sufficiently.
None of the test bullets experienced any fragmentation thanks to their bonded design, which seals the lead core to the copper jacket. The bullets tested were designed for law enforcement use, but in the civilian market, Federal’s Hydra-Shok is an excellent choice, providing 100-percent weight retention, penetration, and expansion in a reduced recoil load available in a variety of personal defense calibers.
Another outstanding round is Winchester’s Supreme Elite Bonded PDX1. The FBI has selected this round as their standard service ammunition based on its performance in their ballistics testing. A bonding process ensures that the bullet will retain all of its weight, while the hollow point design ensures reliable expansion across a range of velocities and distances. The shell cases are also nickel plated for reliable pistol chambering and ejection.
One round I have tested that does not require any bonding is Cor-Bon’s DPX, a solid copper hollow point bullet. I fired this round in .40 S&W through .75-inch pine board, and it penetrated the board completely, expanding reliably and with zero fragmentation. According to Cor-Bon, this round will produce a consistent 12 to 17 inches of soft tissue penetration, even through barriers such as clothing and glass, and will expand to as much as 200 percent of its original diameter.
With law enforcement demanding more effective loads, ammunition manufacturers are happily delivering the goods, and those of us in the civilian self-defense market are the beneficiaries. However, no matter how effective the round you choose, how reliably it expands, or how well it penetrates, misses don’t count. In the end, no matter the round you choose, shot placement is the final determining factor in surviving a life-threatening encounter.
On TV and in the movies, we often see people flying backwards after they have…
by Personal Defense World / Nov 6, 2012