In the initial stage of testing police ammo (1972 to 1973), we recommended that Dallas replace its lead roundnose (LRN) ammo with a then-new Winchester load that pushed a 158-grain lead hollowpoint (LHP) bullet at what today would be +P velocities. We based our decision largely on a military method of measuring temporary wound-cavity volumes in ordnance gelatin that we modified for handgun ammunition. The program’s success led to the lab obtaining better chronographs and formulating a plan to evaluate as much commercial handgun ammo as we could.

With the chronograph upgrades, we could make simultaneous readings of a bullet’s entrance and exit velocities by placing independently wired chronograph screens on either side of the gelatin block. The new setup also let us gather more data, and we crunched them in a number of ways.

As with the .38 Spl., we tested other police cartridges by first evaluating the original load for each. For the .357 Magnum, it was the old 158-grain lead semiwadcutter; for the .45 ACP, we used the 230-grain FMJ roundnose. We used test firearms that were common to police carry, not unrealistically long test barrels. You can see these “baseline” wound volume numbers in the accompanying chart plus a range of newer loads we tested. Remember that the 10mm and .40 S&W cartridges didn’t exist then. Don’t be surprised that we included the .41 and .44 Magnums. A fair number of Texas cops packed the big revolvers in those days.

As we moved to newer ammo types, we continued to review officer-involved shootings to sharpen our ability to predict the success or failure potential of a load. Some of the newer .357 Mag. HP loads posted very high numbers in our tests, with temporary wound cavities often six times larger than the baseline .38 Spl. LRN could manage. And this, good reader, is where reality clashed with theory as we discovered that the military wounding standards we borrowed were too narrow for expanding handgun bullets.

A Typical “Failure” Scenario
A single incident will suffice to illustrate our problem; many others had similar elements:

Two patrolmen asked a man for identification. Instead, the suspect produced a .25 ACP pistol and dropped one officer with a bullet to the kneecap. The second officer quickly emptied his .357 Mag. revolver at close range, only to watch the suspect stroll away as if nothing had happened, still holding the little pistol at his side.

The uninjured officer managed to fumble three or four fresh cartridges into his revolver and ran after the suspect. He yelled to turn the man and was taking up the trigger slack when the suspect’s eyes rolled back in his head and he fell. He had been hit hard in the first volley, but the effects were delayed. The injured officer recovered uneventfully, but the shooter remained comatose and died about a week later.