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.45 ACP vs. 9mm: Which Bullet Is the “Best?”

Glock 19X. Image Credit: Creative Commons.
Glock 19X. Image Credit: Creative Commons.

Oh brother, here we go. This gun writer is going to take a break from writing about Glocks and jump into the neverending .45 ACP vs. 9mm caliber debate.

Gun experts on both sides of the argument find it repetitious and tiresome.

Yet just like a train wreck, you can’t help but look. The time has come, then, for me to share my thoughts on the matter. (“Once more unto the breach, dear friends, once more.”) 

9x19mm Parabellum History

The 9x19mm Parabellum is the older of the two cartridges. It came to us in 1902 by way of Georg Luger and his P08 Parabellum pistol, itself better known as the Luger in honor of its inventor and easily one of the most recognizable handguns ever made. The Luger was arguably the world’s first truly successful autoloading military handgun, and it was certainly battle-tested at the hands of Kaiser Wilhelm’s troops in the First World War. 

Other pistols in the caliber soon followed, including the Browning Hi-Power, Swedish Lahti, and Walther P-38 – eventually the 9mm became the most widely issued military and police handgun cartridge in the world. For several decades it was more popular in Europe than in the United States. But in the 1980s, American police started transitioning en masse from revolvers to semiautomatic pistols, and the U.S. Armed Forces adopted the Beretta M9. The 9mm had planted a firm foothold in the American firearms market. The array of different makes and models in this caliber is simply dizzying. 

.45 ACP History

This one first appeared in 1905, but the caliber truly became established in 1911 thanks to arguably the greatest gunmaker of all time, John Moses Browning, and his M1911 single-action semiauto pistol. This was one of Browning’s three most enduring inventions, along with the M2 “Ma Deuce” .50 caliber machine gun, and the aforementioned Hi-Power. The venerable and ubiquitous pistol passed a 6,000-round torture test in order to become the U.S. Armed Forces’ first-ever semiautomatic pistol. It was also the most powerful handgun ever adopted for issue to general military personnel, serving faithfully in that role for 75 years before the M9 took its place. 

The M1911 pistol is still incredibly popular with shooters around the world. Though the variety of brands, makes, and models isn’t quite as extensive as that of the 9mm, there’s still plenty to choose from, with makers ranging from Glock to Smith & Wesson and SIG Sauer, to name but a few. 

Which Is Best?

Much depends on how you define “best.” Contrary to the old advertising slogan, one size does not fit all.  

For the longest time, it was accepted that the .45 ACP was the superior cartridge. The paradigm was established by the late Julian Hatcher, a U.S. Army Major General and former technical editor for the NRA’s American Rifleman. In his famed Theory of Relative Stopping Power (RSP), Hatcher concluded that the .45 ACP full metal (FMJ) bullet is twice as effective as a 9 mm equivalent.

Maj. Gen. Hatcher based his conclusions on the Thompson-LaGarde tests of 1904, wherein then-Capt. John Thompson – the eventual inventor of the Tommy Gun – and Maj. Louis LaGarde shot steer and human cadavers in order to assess bullet effectiveness. This in turn was pushed heavily by none other than “The Father of Modern Handgunning” himself, the late great Lt. Col. Jeff Cooper, and one of his apt pupils, Chuck Taylor – a former Special Forces officer in Vietnam – of the American Small Arms Academy. They were quite influential in their advocacy for the .45 ACP cartridge and their derision of the 9mm.

Granted, Cooper and Taylor could base their beliefs on tons of combat experience. Granted, when restricted to using military-grade, Geneva Convention-approved ball ammo, the bigger bullet did provide a significant stopping-power advantage. But as Gabe Suarez of Suarez International points out:

“9mm holds more ammo and more ammo is a definite asset in a gunfight. I had a student that was attacked by three guys and his 1911 barely had enough. Another bad guy and he would have been screwed…With modern ammo there is virtually no difference in performance in the typical CCW loads (9mm, 40, 45).” [Emphasis added.] Such modern ammo examples include Corbon DPX, Remington Golden Saber, and Speer Gold Dot.” 

Me personally? Truth be told, I have a sentimental attachment to both cartridges. On one hand, as I have mentioned ad nauseam, the very first pistol I fell in love with was a 9mm Beretta 92F. On the other hand, my first firearms purchase was a .45, namely the Springfield Armory M1911-A1

Having attained numerous marksmanship accomplishments with both calibers, in official qualification courses and competitive matches alike, I can tell you this much: The 9mm gives me lesser recoil and more rounds in more compact packages, but the .45 ACP gives me slightly better accuracy.

The bigger bullet also gives me a certain degree of added psychological comfort, especially when I see the fist-sized hole that 25 rounds of the latter caliber leaves at 7 yards. The bigger .45 ACP can also give you an edge in competitive shooting.

A near-miss against the X-ring with a 9mm may just barely cut the line of the X with a .45, but that is sufficient to earn the higher scoring value.

But from a CCW standpoint, though I have carried a .45 in the past, the 9mm is simply more pragmatic for me, especially with my lower back issues. 

Use what works best for you. 

Glock 19X

Glock 19X marketing package. Image Credit: Glock.

Glock 19X

Glock 19X. Image Credit: YouTube Screenshot.

Glock 19X

Glock 19X. Image Credit: Glock.

Glock 19X

Glock 19X. Image Credit: Creative Commons.

Christian D. Orr has 33 years of shooting experience, starting at the tender age of 14. His marksmanship accomplishments include: the Air Force Small Arms Ribbon w/one device (for M16A2 rifle and M9 pistol); Pistol Expert Ratings from U.S. Customs & Border Protection (CBP), Immigration & Customs Enforcement (ICE), and the Federal Law Enforcement Training Center (FLETC) Criminal Investigator Training Program (CITP); multiple medals and trophies via the Glock Sport Shooting Foundation (GSSF) and the Nevada Police & Fires Games (NPAF). Chris has been an NRA Certified Basic Pistol Instructor since 2011.  In his spare time, he enjoys (besides shooting, obviously) dining out, cigars, Irish and British pubs, travel, USC Trojans college football, and Washington DC professional sports. 

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Written By

Christian D. Orr is a former Air Force officer, Federal law enforcement officer, and private military contractor (with assignments worked in Iraq, the United Arab Emirates, Kosovo, Japan, Germany, and the Pentagon).