There is an interesting pattern with people who are looking for the best possible defensive pistol ammo and yet are drawn to questionable unproven solutions that feature misleading information to sell it. They buy the questionable ammo and defend it while repeating advertising claims without having an understanding of how it actually compares to known good options as well as the most basic options. Most people do not have a basic comprehension of what a pistol bullet does and that leads to falling for concepts like “knock down power” and “energy transfer” as selling points. The ads provide absolutes or comparisons without addressing what the product is being compared to.
Knowing and accepting that duty and sub caliber pistol rounds are just poking holes is a good first step. Many people would benefit from understanding the three ways gunfire can stop a person (psychological, exsanguination, and CNS disruption) and then know and recognize pistol full metal jacket (FMJ) ammunition as a baseline of performance. FMJ is one of the most basic forms of ammunition and is widely available. To understand FMJ performance, a working knowledge of what calibrated ballistic gel testing is, does, and what we should be looking for is quite important. How many people watch a gel test without knowing what they are looking at or what they should be looking for? I would guess at least 95%.
Most ballistic gel testing is boring. If an ad or video makes it exciting or dramatic- there is something wrong with the product. Their presentation is making up for lack of claimed performance. I have not seen many popular YouTube videos covering basic FMJ.
If more people understood FMJ performance, a lot of these questionable ammo types would fade away because people would know better. Comparing FMJ to a well-designed jacketed hollow point (JHP), like Federal HST, we quickly see FMJ typically can penetrate considerably further in organic/gel type structure but can have difficulty in barrier penetration. A well designed/made bonded JHP can provide superior barrier penetration. FMJ can be impressive compared to what we are used to seeing in gel tests- normally performance floating around the FBI standard of 12″-18″ of penetration give or take 10″. Most shared testing focuses on that FBI standard. FMJ can kill but has some disadvantages at that task compared to HST. A good quality JHP will have a controlled penetration that can be achieved through its expansion. The expansion acts like a parachute, slowing the projectile down to a point where it could pop out of the other side of the threat. It is common to find fired projectiles caught in clothes after completely going through a person or found just inside the skin on the other side from the entry point. Some recent gel testing we did with HST showed the projectile pop out from the opposite side of the block not damaging anything it bounced off.
With all this there is something to remember- we want expansion, but we need penetration. Insufficient velocity, too little weight, too much expansion can lead to shallow wounding which is poor penetration. Without needed penetration incapacitation is limited.