9mm vs .45 ACP

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A 9mm is generally cheaper, has less recoil and higher velocity than a .45 ACP. The .45 ACP (Automatic Colt Pistol) cartridge holds bullets that have a diameter of .452 inches (11.5mm) so it is slightly larger than the 9mm (.355 inch bullets). Both cartridges have a long history and were first designed over 100 years ago.

Comparison chart

.45 ACP versus 9mm comparison chart
	.45 ACP	9mm
	current rating is 3.63/5 1 2 3 4 5 (559 ratings)	current rating is 3.53/5 1 2 3 4 5 (893 ratings)
Bullet diameter	.452 in (11.5 mm)	9.01 mm (0.355 in)
Neck diameter	.473 in (12.0 mm)	9.65 mm (0.380 in)
Case type	Rimless, straight	Rimless, tapered
Base diameter	.476 in (12.1 mm)	9.93 mm (0.391 in)
Designer	John Browning	Georg Luger
Rim diameter	.480 in (12.2 mm)	9.96 mm (0.392 in)
Place of origin	United States	German Empire
Case length	.898 in (22.8 mm)	19.15 mm (0.754 in)
Maximum pressure	21,000 psi (140 MPa)	235.00 MPa (34,084 psi)
Overall length	1.275 in (32.4 mm)	29.69 mm (1.169 in)
Velocity	700 - 1150 FPS	950-1400 FPS
Rim thickness	.049 in (1.2 mm)	0.90 mm (0.035 in)
Used by	United States and others	NATO and others; Militaries, police, and self defense.
Penetration	11.3-27”	8 - 40" (13')
Designed	1904	1901
Type	Pistol / Revolver / Carbine / SMG / Derringer	Pistol / Revolver / Carbine / SMG / Derringer; Cartridge
Cost	More expensive than .40 S&W and 9mm	Cheaper than .40 S&W & .45 ACP
Variants	.45 ACP +P, .45 Auto Rim, .45 Super	9 mm NATO, 9×19mm Parabellum +P, 9×19mm 7N21 +P+, 9×19mm 7N31 +P+
Primer type	primarily large pistol (but also small pistol in some brass)	Berdan or Boxer small pistol
Case capacity	25 gr H2O (1.625 cm³)	0.862 cm³ (13 gr H2O)
Expansion	0.45-0.79”	0.36-0.72"
Felt Recoil	Heavier and pushes one's hands backwards instead of up. Does not have much muzzle flip.	Less recoil.
Magazine Capacity (as shipped from factory)	6-14	6 to 20
Wars	World War I – present	World War I–present
Muzzle Energy	369 lb/ft (230gr at 850FPS)	304 lb/ft (124gr at 1050FPS)

A close-up of .45 ACP which shows what the primer cap looks like after the round has been fired and ejected from the chamber. The depression in the center is where the firing pin struck the primer cap.

Specifications

The 9mm has a bullet diameter of 9.01mm (0.355 in), a neck diameter of 9.65mm, a base diameter of 9.93 mm, a rim diameter of 9.96mm and a rim thickness of 0.90 mm.

The .45 has a bullet diameter of 11.5 mm (.452 in), a neck diameter of 12.0mm, a base diameter of 12.1 mm, and a rim diameter of 12.2 mm.

A line-up of pistol and rifle cartridges. From left to right: 9 mm Luger Parabellum, .40 S&W, .45 ACP, 5.7x28mm, 5.56x45mm NATO, .300 Winchester Magnum, and a 2.75-inch and 3-inch 12 gauge.

Penetration

A 9mm averages between 8” and 15.9” penetration. However, the Winchester FMJ has a penetration of 24.5” and the Doubletap JFN+P trail defense has a penetration of 40”. The cartridge expands to approximately 0.35 to 0.72”.

A .45 averages about 11.3”-14.3” penetration. However, the Remington FMJ has 27” penetration. The cartridge expands to an average of 0.75” inches, but the Remington FMJ expands to 0.45”.

This is a video of a penetration tests with the 9mm and .45 ACP.

Magazine capacity

Due to the smaller size of the round, 9mm guns typically have a higher magazine capacity than a .45, although the specifics vary depending on the type of gun. For example, the Glock 17 holds a standard 17 rounds of 9mm, while the Glock 21 holds a standard 13 rounds of .45.

Recoil

A 9mm has less recoil than a .45. This improves accuracy, and makes the 9mm easier to handle.

Velocity

A 9mm fires bullets with a velocity of between 990 and 1350 feet per second.

A .45 fires bullets with an average velocity between 835 and 1150 feet per second.

Cost

A 9mm gun costs between 40% and 50% less than a .45.

Production History

The 9mm cartridge was designed by Georg Luger in 1901. It has been produced since 1902.

The .45 was developed by John Browning in 1904. It has been used by the United States and other militaries since World War I.

Evolution and Usage

The 9mm cartridge was developed from Luger’s 7.65x21mm Parabellum. The bottleneck of that cartridge was removed, leaving a tapered, rimless cartridge. It was adopted by the German Navy in 1904 and the German Army in 1906. It became more popular after World War I and has since become the most common caliber for U.S. law enforcement agencies and for military and law enforcement agencies around the world. It is also popular for self-defense.

The .45 was developed by the U.S. Cavalry in the late 1890s and early 20th century in a bid to create a bullet that was more effective against determined opponents. It was intended to be a “real man-stopper.” It was adopted by the United States Army in 1911.

9mm vs. .45 ACP