Is it the size of the hole on paper that counts in a carry caliber or a system that will give quick and repeatable hits when the gun is small enough to carry with you on a daily basis? The vast majority of the arguments revolving around it remain based on the same broken premise that is the so-called “stopping power” whereby handgun bullets have a magic on or off button associated with them. They do not. The use of handguns is a cheap instrument, and they seldom have a dramatic outcome. The most acceptable expression of it is still that of Clint Smith: “They poke holes.” A bigger bullet makes a slightly bigger hole, however when that hole does not go through the structures that put a body to a standstill, caliber becomes a trifle.
It is here that the current discourse comes in handy: rather than mythology, it is pinned down to penetration and manageability. The 12 to 18 inches calibrated ballistic gel standard put in place by the FBI over its long history is there because fights do not occur as clean, square-range demonstrations. Arms may conceal torsos, individuals can turn, and the bullets must reach one of the vital qualities after penetrating the intermediate tissue and bone. Gel is not part of the human body, but it happens to be a repeatable yardstick. Once a load constantly falls short, the error buffer falls very quickly. When it goes completely out of the window, the probability of a bullet to leave the danger and proceeds is no longer speculative.
That leads to the hidden-carry triangle that does count: terminal performance (penetration first, followed by expansion), shootability (follow-up shot recoil and recovery), and capacity (this is actually what the platform can hold). The “best” caliber is generally the one that holds that triangle balanced within this or that gun that one will carry, and with ammunition that runs well in that particular gun.
Small calibers are operable, however they require candor regarding limitations. .22 LR can hit the yardstick in penetration with the appropriate load and low recoil means that the practice becomes less challenging. The weakness of the trade is rimfire reliability and that there are loads which simply do not penetrate adequately out of short barrels. .22 WMR tends to penetrate better when snubbed, but remains in the rimfire reliability game and usually has fewer practical carry-guns.
In the case of pocket pistols, “in-between” calibers start to take shape, as the .32 ACP offers centerfire ignition and minimal recoil, and the heavy FMJ loads can be very penetrating, but magazine geometry and overall length of ammo may cause headaches. The renewed.32 H&R Magnum and .327 Federal Magnum demonstrate how a revolver can defy the capacity issue- usually by adding a round- and maintain solid penetrations; the price is blast and recoil, particularly with the hotter.327 in short barrels.
380 ACP is loaded-sensitive in the most common footprint of a micro-pistol. Heavy clothing gel testing has demonstrated that the cartridge tends to arrive at an either/or position either sufficient penetration and no expansion, or sufficient penetration and insufficient expansion that can fall short. The identical method of testing, but with short carry barrels and a clothing barrier has then been applied to compare concealable handguns at 10 feet into synthetic gel, which assist in revealing which loads remain constant when the velocity decreases.
The reason 9mm has remained the default is not because it is mystical, but because it tends to strike a balance between the triangle: high enough ammo design maturity, low enough recoil on most handguns, and high enough capacity in small frames. .38 Special and .357 Magnum are still viable in revolvers, but load choice and location become more than an esoteric issue.
Ultimately the caliber question is transformed into a skills question. The compilations of real incidences have demonstrated groupings of the common service calibers closer than an individual anticipates, such as the mean of approximately 2 hits to incapacitate with several key rounds of a handgun in one large set. That fact drives the decision back into what can be carried, shot on demand under stress and fed a load that penetrates so that it counts.
