Caliber talk is loud because it is reassuring that a cartridge can fix a problem when it comes in physical contact. It cannot. In the real world, handgun conflicts value reliability, manageable recoil, and bullets penetrating vital organs- and the stress reaction of the shooter attempts to destroy fine motor control.
That renders the term fails under stress to be less about internet swagger and more about predictable modes of failure: ignition issues, shallow penetration, unpredictable expansion, over-blast or recoil, which slows the use of accurate follow-up shots. As indicated by the cartridges below, training circles and incident data turn around to indicate recurring locations of small margins turning out to be large liabilities.
1. .22 Long Rifle (rimfire) for primary carry
22 LR can be shot well on a dry range day but the elephant in the room is the rimfire ignition. Misfires occur frequently to be significant when there is no time to tap-rack and troubleshoot. A variety of .22 loads find it difficult to pass the 1218 inch yardstick of FBI test penetration through clothing and at lower velocities due to short barrels, especially terminally.
There exist a few modern defensive loads in.22 that go even deeper yet the cartridge remains on thin ice in terms of reliability and consistent penetration. When the shooter is made to squeeze the trigger harder due to stress, the price of a click rather than a bang becomes horribly apparent.
2. .25 ACP in pocket pistols
The 25 ACP was meant to be able to perform the same as.22, but with centerfire reliability, and it can be made to do so, although with a much lower penetration and tissue disruption than a modern defensive standard. Recurring real incident lists indicate better non-incapacitation rates with smallest centerfire pistol calibers; one data set by Greg Ellifritz found a 35% failure-to-stop in.25 ACP. That figure does not imply that the round is not harmful. It implies that the user is literally buying time that he or she might not be having. Take into consideration the fact that the most popular pistol by the point of our discussion, the .25, will have small sights and a poorer grip, and the theoretical stability of the cartridge will be watered down quickly.
3. .32 ACP when penetration is inconsistent
ACP provides light recoil and small arms, although most loads do not match modern service rounds, and instead are competing with the .22 LR. The expansion is commonly load-dependent and may become uneven with clothing and in most configurations, it cannot provide the depth necessary to be able to reach critical anatomy consistently. The cartridge in Ellifritz compilation takes the rate of failure-to-stop at 40 percent, a not-too-sobering number before considering the older platforms which are often chambered to take it. .32 can be shot by recoil-sensitive shooters; it only requires a concession of small margin.
4. .410 shotshell loads in revolvers
The sale that handgun-sized .410 guns promulgate is point, shoot, and leave the rest to spread. The fact is that short barrels and gaps in the revolver cylinder bleed velocity and most birdshot loads do not penetrate significantly. Patterning is a two-sided sword as well, broad patterns at room lengths make the chance of a partial hit and pellets finding their way where they did not belong. Buckshot loads are capable of tightening the equation at short ranges, although performance remains highly dependent on particular ammunition and distance and the platform presents tradeoffs in the control of the trigger, recoil, and accuracy. The concept of close enough is a poor bet under a condition of stress.
5. .380 ACP, especially with short barrels and the wrong load
380 is capable of working but can frequently only work when the ammunition is carefully selected and the shooter can hold the gun flat when making quick strings. A high percentage of the popular hollow points swell before they get to the point of penetration that is of the most importance. Other loads pierce, but swell little, diminishing the benefit that people purchase the caliber of in the first place. The cartridge is also found in ultra-compact pistols in which recoil may seem snappy, sights may be short, and malfunctions may be more frequent, as long as grip technique becomes ineffective when adrenaline drives. Simply put: the round is both doable but not generous.
6. 10mm Auto for typical concealed-carry problem sets
With 10mm, one may carry serious power and considerable penetration rates, yet the recoil of the rifle is a stress and a punishable one. Blast and muzzle lift also cause slow follow shots and the more is better reputation of the cartridge tempts shooters to loading levels far in excess of that necessary to deal with two legged threats. Comparisons of typical handgun calibers indicate that most service level ammunition groups much tighter than many would assume and that the capability of the shooter to deliver multiple shots in a short period predominates the results. The wound ballistics research of the FBI has long stressed that penetration depth is of more importance than caliber itself, and that the additional power of 10mm does not overcome that issue. It merely puts an element of control that a number of shooters fail to handle during the stress.
7. .38 Special from ultra-short “snub” barrels
38 Special is full of decades of street history, but physics does not respect tradition. Shooting less than two inches barrel is known to slow down the velocity and cause hollow-point expansion to collapse and to reduce the consistency of penetration, +P loads often add recoil and can blast out without increasing the shortest tubes performance proportionally, and recoil can open up groups when the shooter has a heart attack. The studies into marksmanship under physical strain demonstrate that shooters are able to sustain the accuracy of hits even when under extreme exertion, and the alteration of dispersion under stress, as well as snub-nose sights and triggers, do not help.
The cartridge is still capable of doing it, although the shortest platforms still require a selection of loads and drilled practice. All of these cartridges are magic failures, and all of the good calibers are magic solutions. This trend is easier to follow: small or uneven rounds decrease the margin of penetration and reliability, whereas big recoil rounds decrease the margin of accurate and fast hits. Where stress is the constant, the formula used to win remains unvaried, a good handgun, a cartridge that can be controlled, and ammunition that penetrates sufficiently-supplanted by sufficient training that the shot will be accurate when needed.
