Yes, again. Amongst avid handgun fans the debate between big and slow versus small and fast stretches back over a hundred years now I'd guess. Next year marks the 100 year anniversary of the Government Model 1911 .45ACP having been adopted by the U.S. Military (even though it existed in 1904) and the 9mm is even older than that. What makes the debate relatively new (and hopefully interesting) is the addition of what I call "compromise calibers". There are a couple in between the maximum ends of the debate and recently that has been thrust into my consideration almost against my will.
What I refer to as Compromise Calibers includes anything that is between the 9mm and the .45ACP is size (10mm, .40S&W, etc) or a production caliber (as compared to a custom-only wildcat cartridge) that changes the basics of either such as the .357Sig or the .45GAP. Arguably the first compromise caliber (in a pistol) was the 10mm presented in the early 1970s, but before we get into that, let's talk a bit about the compromise being made.
Way back when the U.S. Military discovered that the .38 caliber bullets they were firing from their revolvers were not delivering incapacitating injuries to the enemy. That's not to say that the injuries weren't fatal - just not immediately so. Of course, 100 years later we have thoroughly documented (now) that an injury isn't immediately fatal unless it hits the Central Nervous System (brain or spinal cord) and even then, if it's a spinal cord shot it may only be incapacitating, not immediately lethal. That's why our bullet designs and caliber / velocity pairings focus on doing as much damage as possible to large blood-bearing vessels and organs so as to cause the enemy to bleed as much as possible as fast as possible to shut down their system. In other words, we cause injuries that make them bleed to death (or close to it).
Now, I know that police officers and deputy sheriffs and every other variant of law enforcement professional in the country today doesn't shoot suspects with the intent of killing them (and if you did, you'd be a fool to admit it). Instead, you deliver shots to the center mass of the suspect when justified in an attempt to incapacitate them as quickly as possible thereby stopping the threat to you, your partner and all bystanders in the area. That's your job. Writing for soldiers can often be easier: soldiers kill the enemy. That's what they do. "Overkill" is a political term of concern. Screw that. I used an AT-4 to stop that enemy truck? Yeah? The problem is? My booby-trap had two grenades instead of one which would have been sufficient? What's your point? You get the message. Law enforcement has to be far more careful about what they write and say. That means that the people who design ammo and weapons also have to be careful what they say in sales pitches.
Keep all of that in mind as we discuss a few compromise calibers, focusing down on one, and the pros / cons to be had.
So the compromise is a balance sought between carrying as many rounds as we comfortably can of a caliber that will do sufficient damage to the enemy or suspect when necessary and deliverable from a firearm that can be conveniently worn or carried. Agreed? Cool.
As we've identified the 9mm and the .45ACP as the genesis of this debate if you will, let's talk about them briefly. Both created before 1900 and both packaged in relatively concealable carry packages (i.e. the Browning High Power or the Government Model 1911), they offer a choice:
or do I want to carry fewer rounds of a larger caliber bullet that exit the barrel slower?