There is an on-going discussion about which caliber of handgun ammunition offers the best stopping power. The great stopping power myth is that there is a “best.” Given the composition of current ammunition the fact is that there is no single ammunition today that can reliably claim to have superior stopping power.
The ammunition most commonly carried for self-defense and by law enforcement officers today is typically in one of five calibers, including .38/.357, 9mm, .357 SIG, .40 S&W, and .45 ACP which are made by a variety of ammunition manufacturers. Often, these self-defense rounds have hollow-points or expanding full metal jackets.
Of course, these different ammunition rounds perform differently but all can produce the desired result—the stopping of a deadly attack. There seems to be no “best” round to do that; rather, stopping power seems to be more correlated with shot placement rather than any particular round.
Factors Affecting Stopping Power
For us, stopping power is the ability to eliminate the “bad guy’s” ability to offer resistance or to remain a threat.
Two variables affect stopping power: kinetic energy and shot placement.
Many shooters believe that the capacity of a bullet to produce a large amount of kinetic energy will result in greater stopping power. So how does ammunition accomplish this? Shooters have two options: use a large caliber round with high velocity or use any caliber ammunition and focus on accurate shot placement.
Accurate Shot Placement
We believe that accurate shot placement is the most realistic option for stopping a threat—not the caliber of the ammunition. If a shot is accurately placed in a location that can create sufficient penetration and expansion then the round will cause enough internal damage to stop the threat. No matter the caliber of the round its ability to stop a threat depends on whether or not the shot is placed accurately to hit a vital structure in the bad guy’s body.
Of course, you want to use high-quality self-defense ammunition that lives up to its claims of penetration and expansion but these two factors—penetration and expansion—create the most stopping power potential but ultimate stopping power rests with your training with your weapon system.
Accurate hits with the common self-defense rounds will “stop” a person if the hits create sufficient brain or spinal cord damage or if the bad guy loses enough blood to lower his or her blood pressure and the brain cannot function. A bad guy’s effectiveness can also be diminished if a round shatters a major bone (for example, the pelvic girdle), but that shattered bone may not be enough to stop a fight.
A Final Word About Stopping Power
Dr. Sydney Vail, and associate professor of surgery in a Penn State trauma center, says:
“Stopping power is a marketing tool and should be dropped from our discussions of ballistic performance until such time as ammunition effectiveness is measured by more means than just the results of gelatin and barrier tests. When ammunition companies or regulatory agencies begin to use computer simulations, simulant tests, animal models, autopsy results, and trauma surgeon operation reports with hospital summaries to determine the effectiveness of their products, then we will know which ammunition can be labeled as having the ‘best stopping power.’ And this claim will be based on scientific data rather than incomplete ballistic testing.”
Until then, shot placement with any commercially available self-defense ammunition will offer you the best chance of maximizing your ammunition’s stopping power.
The Great 9mm Versus 40 Caliber Debate
One of the current trends in the firearms world is the return to 9 mm ammunition. The FBI started using 9mm ammunition after finding that 40 Smith and Wesson rounds were causing too much excessive wear to their firearms. Here is a summary of their justification (from http://looserounds.com/2014/09/21/fbi-9mm-justification-fbi-training-division/)
- Caliber debates have existed in law enforcement for decades
- Most of what is “common knowledge” with ammunition and its effects on the human target are rooted in myth and folklore
- Projectiles are what ultimately wound our adversaries and the projectile needs to be the basis for the discussion on what “caliber” is best
- In all the major law enforcement calibers there exist projectiles which have a high likelihood of failing LEO’s in a shooting incident and there are projectiles which have a high ting incident likelihood of succeeding for LEO’s in a shooting incident
- Handgun stopping power is simply a myth
- The single most important factor in effectively wounding a human target is to have penetration to a scientifically valid depth (FBI uses 12” – 18”)
- LEO’s miss between 70 – 80 percent of the shots fired during a shooting incident
- Contemporary projectiles (since 2007) have dramatically increased the terminal effectiveness of many premium line law enforcement projectiles (emphasis on the 9mm Luger offerings)
- 9mm Luger now offers select projectiles which are, under identical testing conditions, I outperforming most of the premium line .40 S&W and .45 Auto projectiles tested by the FBI
- 9mm Luger offers higher magazine capacities, less recoil, lower cost (both in ammunition and wear on the weapons) and higher functional reliability rates (in FBI weapons)
- The majority of FBI shooters are both FASTER in shot strings fired and more ACCURATE with shooting a 9mm Luger vs shooting a .40 S&W (similar sized weapons)
- There is little to no noticeable difference in the wound tracks between premium line law Auto enforcement projectiles from 9mm Luger through the .45 Auto
- Given contemporary bullet construction, LEO’s can field (with proper bullet selection) 9mm Lugers with all of the terminal performance potential of any other law enforcement pistol caliber with none of the disadvantages present with the “larger” calibers
- Some 9 mm vs. 40 Caliber Comments by Law Enforcement Officers—Friends of Spartan Firearms Training Group
“If I had to select a gun for a large number of people to use, I would pick the g19. I even bought myself a gen 5. Modern ammo choices have pretty much ended the 9-40-45 debate. And with the adjustable back straps, the Glock is even more adaptable.”
“The duty ammo we use has less than a 10% difference between the performance 9mm and the 40 S&W. The 9mm gets you less recoil and more rounds than the 40. Frankly, handguns are more about shot placement and a whole host of variables that are beyond your control when you are involved in a gunfight. For the record, I have seen someone with four full penetration wounds from a 5.56 round stay in the fight, and survive their wounds.”
“They also found the 9mm G2 round to be more effective than the .40 180 grain round. When you factor everything in it’s a no brainer. Hopefully my agency will be switching to the Gen 5 Glock 17 in the not too distant future.”
“I have advocated for years for us to issue just the G19. But, people seem wrapped up in the idea that you have 6 more rounds with a 17, and a slightly longer sight radius. If 46 rounds of 9mm won’t solve your problem, 52 won’t either. And really, does anyone really think the bigger sight radius matters in a 7 yard or less gun fight?”
“It’s widely known there’s not much difference between the two ammunition’s. It appears Federal agencies prefer the .40 cal based on availability and number of agencies that currently have contracts with vendors already in place…A lot of local and state agencies have already transitioned to 9mm.”
“40’s time has come and gone. 9mm has caught up and surpassed.”