Shooters can be an opinionated lot. Get a few gun guys in a room and start talking ammo, and it’s usually not long before it breaks down into debate about which cartridges reign supreme. But does it make sense? Does it still make any practical difference whether a shooter in a self-defense situation is carrying a 45 Auto or 9mm Luger or 25 Auto—or anything in between?
To stop a threat, a handgun bullet must physically hit vital organs. Period. Unlike rifle cartridges, which carry a massive amount of energy that damages tissue well outside the actual bullet path, the damage caused by a pistol projectile is limited to the actual crushing path of the bullet. This is true from the largest handgun cartridges to the smallest.
To that end, bullets must penetrate deep enough and in a straight line. This was once easier said than done. A lot has changed in the 100-plus years since many of our most-popular handgun cartridges came to be. Cartridges had only recently made the switch from black powder to smokeless, and most bullets were simple jacketed soft points.
In those days, bigger bullets fired from larger cartridges admittedly had an edge. With less reliable expansion and lower weight retention, a larger projectile stood a better chance of penetrating to the necessary depths. That’s where cartridges like the 45 Auto earned their reputation and smaller ones suffered.
But now, engineering and construction differences have totally changed the landscape. The best modern, controlled-expansion bullets pushed at consistent velocities hit those critical depths regardless of the specific cartridge.
Despite the similarities, there will always be some physics-driven performance differences that simply can’t change—no matter how far bullets advance.
For example, an expanding 380 Auto bullet will never penetrate as deep as a comparably built 45 Auto bullet fired through the same barriers.
But it’s not a question of which calibers penetrate or expand the most—its whether they meet penetration thresholds. An attacker hit in the vitals with a 45 Auto is no more incapacitated than one hit in the same spot with a 380 Auto. Conversely, an attacker hit in a non-vital area (or missed entirely) is unlikely to be stopped, regardless of the caliber.
Equal Playing Field
That’s where modern cartridge discussions boil down. With modern, proven designs like Speer Gold Dot, Gold Dot G2 and Gold Dot Carry Gun, penetration depths and expansion are engineered, predictable and consistent, so their ability to reach critical depths without over-penetrating isn’t in question.
With rounds like these at their fingertips, shooters are much better served to choose a cartridge based on their ability to shoot it with speed and accuracy, rather than perceptions of the load’s stopping power.