.40 or .45?

Understanding how the .40 S&W is a better defense round than a .45 ACP takes a study in the dynamics of many physical properties. I always liken the comparison to asking someone which they’d rather hit with: a volley ball thrown at their chest at 30mph or a golf ball at 30mph?

This does in fact represent an exaggerated example, but the basics remain the same throughout. A typical 230 grain .45 ACP round will be moving at approximately 800 to 1000 feet per second at the muzzle while the typical 165 grain .40 S&W projectile will be traveling approximately 1000 to 1200 feet per second. Conventional wisdom dictates that despite the slower velocity of the .45 caliber projectile the difference in weight and kinetic energy gives the bigger round more knock down power. It’s the old “bigger is better” theory. However when we’re talking about a firearm’s ability to stop an aggressor from having the capacity to inflict harm upon others, old wives tales do not apply. Science and physical facts are the important indicators. When it comes to statistical data, there is no argument that in the 2 decades since it’s introduction the .40 cal has proven itself a formidable defensive option but overcoming the 10 decades and nearly 4 generations of testimonial usage of the venerable .45 make for an almost impossible task of convincing anyone that sometimes smaller is at least as good, if not better.

Having seen documented statistics of nearly all offerings of commercially available ammunition for both the .40 and .45 in bullet weights ranging from 135gr to 180gr in .40 and 180gr to 230gr in .45, and only looking specifically at the most commonly used weights for each respectively it was obvious and undeniable that the .40 cal could indeed meet and in some cases exceed the penetration of the .45 in ballistic gelatin. Also noted was the ability of the .40 to expand to a greater percentage of it’s original diameter and create a wound channel comparable to that of the slower moving .45 projectile which starts out larger, but slows more rapidly upon contact with a media and therefore does not inflict a greater amount of tissue damage as what many perceive based on the “bigger / better” school of thought.

The greater speed of the smaller diameter projectile reduces the snow plow effect of the big blunt frontal cross section of the .45 bullet upon impact and allows it to penetrate more deeply, yet expand predictably and uniformly to dispense it’s energy along the wound channel to incapacitate the target.

Now granted, if given the choice between which one I’d rather be shot with there is no sensible argument that you stand a better chance of surviving one over the other, ergo I would not want to be shot with either one. I would not want to be shot with a .17 caliber air rifle for that same matter as far as that goes. When choosing which one I would rather rely on to defend myself against an aggressor threatening my life or that of others, both are capable of getting the job done but one has slightly better inherent physical properties to get the job done with greater efficiency.

I won’t even throw in the arguments of less recoil, smaller easier to handle pistols and higher capacity capabilities. Those are all trivial in the bigger picture. Maintaining a concentration on actual target performance a 165gr .40 caliber hollow point bullet traveling at 1200 feet per second, penetrating up to 13 inches of gelatin and expanding up to 1.5 times it’s original diameter will reach and inflict greater incapacitating damage to a human subject than a 230gr .45 caliber round moving at 950 feet per second, penetrating 11 inches and expanding 1.25 times it original diameter.

Kind of like comparing the bruises you’d get on your chest from the volley ball and the golf ball.

Of course there are those who will point out emphatically that a .45 will consistently knock down bowling pins as compared to a .40 cal, and that’s a valid argument when talking about bowling pins. If I was confronted with by a bowling pin packing heat and threatening my life, I’d undoubtedly want a .45 to knock it down without question. But seeing as that I’m more likely to be confronted by a 6 foot sack of water, tissue, organs and bones than a 20 inch plastic encased block of hardwood, I’ll take the .40 S&W.

On a non scientific note, one must also look at time and technology. When the .45ACP round was developed, solid rubber tires on wooden rims were the state of the art in performance for automobiles. There is such a thing as “tried and true.” I won’t argue that. But in some cases the best service something that was developed decades ago can provide us with is the ability to study it and make improvements in successive designs.

That is solidly the case where the .40cal round is concerned. After all, before something can be “better than sliced bread” there must first be sliced bread. The .45 is a fine loaf of sliced bread. The .40 simply adds the “better than” part.

MJ McGowan