What is the result when a bullet strikes something that is not a clean, square-on target–heavy cloth, wallboard, sheet metal, angled windshield glass, then must strike, even, something vital?
The question has been of more than caliber folklore in the decades within the FBI within the Ballistic Research Facility at Quantico. Retired FBI expert and 16-year veteran of the facility, an agent named “Scott,” explained a change in the organization to not make informal sidearm decisions when he was there, which he termed as “Hey, this works well for us”, and instead, perform repetitive testing and consider the pistol, ammunition and shooter population as a system.
The 9mm to 10mm to .40 S&W to 9mm long arc that the Bureau had deeply followed was not about a rediscovery of a “best” cartridge. It was a tale of what constituted being “good” in a terminal performance and then subjecting candidate rounds to prove it under predefined circumstances. Scott linked the initial urgency to a special failure of a 9mm load highly popular at the time as opposed to an indictment of 9mm. “It didn’t have the ability to penetrate intervening barriers and then to enter the human target and penetrate deep enough to disrupt a vital organ,” Two special agents “we buried two special agents because of it.” Such an effect caused the FBI to emphasize depth and uniformity, even in cases where the bullets were required to come in at flawed angles and media.
It is why the barrier-and-gelatin protocol was adopted as the engineering language at the Bureau. The medium is intentionally standardized: 10% gelatin blocks that are prepared and calibrated to allow the results to be compared over time, lots and labs. The process of calibration is not an ornament; one of the most popular ways of doing that is to check with a BB when a steel ball has to enter 8.5-9.5 cm at a certain speed. The idea is to test whether a bullet can still propel to the depth that corresponds to vital anatomy even when it is impregnated by clothing, plywood, drywall, sheet metal, or windshield glass – obstacles to clog hollow points, strip jackets or bend noses or to bend paths. The 12-18 inches of penetration in gel is usually referred to as the performance window in this case as shallow tracks may fail to penetrate to the critical structures whereas excessive depth presents its own risks.
At the point where early testing required additional penetration margin, 10mm Auto was providing an alluring solution on paper. Scott said, “There were huge issues for us with 10 millimeters.” Recoil does not even become a personal concern in a big agency, it turns into a fleet-wide variable that determines the qualification score, maintenance cycle, breakages and stops. The 10mm Model 1076 of Smith & Wesson was adopted, however, with Scott indicating that approximately half needed to be reworked by the custom-shop and become a divergent experience between those that ran and those that did not.
When 40 S&W came it was a compressed variant of the same concept- same weight bullets in a shorter case- but the systems issue came back to haunt them as loads and pistol size clashed. Scott explained that small.40s could exhibit durability and malfunction with full-power ammunition, a trend which produced the first fallacy: “Everybody first goes, ‘Hey, what’s wrong with the ammo?’” The other question that was more resilient was the interaction of recoil impulse, slide speed, variability of the shooters and the size of the pistol.
Experiments by the late 2000s were beginning to demonstrate that modern 9mm projectiles were essentially performing as well as.40 S&W in protocol results, even with barriers that had shamed previous designs. Somebody like hornady, said Scott, summarized the working of it, as Dave Emery put it: “Because you allow us velocity.” Manufacturers with 9mm enjoyed a greater velocity range and still remained dependable in a large pistol line, allowing projectile engineering, including bonding, mechanical locking, and controlled expansion, to take the heavy-lifting. It was the bald summary of Emery: “There’s not a nickel’s worth of difference between the two.”
The modification was not limited to gel data. With six out of ten shooters being faster and much more accurate with 9mm than with .40 S&W, first-time shooters and the highest-ranking, Scott reported the same in a controlled FBI course. That was an advantage in the math of the Bureau that a sidearm of duty is issued to thousands, is carried years and fired with stress in people who have uneven hand sizes, training and recoil tolerance.
It is no “9mm won” that takes a while to sink in. It is that the most significant decision the FBI did has been the construction of procurement on predictable behavior of projectiles using realistic barriers and controllability and reliability as engineering requirements, and not debate points.
