Differences between .38 Special and 9mm

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.38 Special vs. 9mm Parabellum

The .38 Smith & Wesson Special and the 9x19mm Parabellum are two centerfire handgun cartridges with long histories of service with military and police forces.[1] The .38 Special was developed by Smith & Wesson in the United States and introduced in 1898 for revolvers.[2] The 9mm Parabellum was designed in Germany by Georg Luger and introduced in 1902 for semi-automatic pistols.[3] While both were created for military use, the 9mm has become the most popular handgun cartridge worldwide, while the .38 Special remains a common choice for revolvers used in self-defense.[4]

The primary design difference between the two cartridges is that the .38 Special is a rimmed cartridge, intended for use in revolvers, while the 9mm is a rimless cartridge designed for semi-automatic pistols.[5] This fundamental distinction influences the types of firearms each is chambered in, as well as characteristics like ammunition capacity.[5]

Comparison Table

Category .38 Special 9mm Parabellum
Case type Rimmed, straight wall Rimless, tapered
Bullet diameter .357 inches (9.07 mm) .355 inches (9.02 mm)
Case length 1.155 inches (29.3 mm) 0.754 inches (19.2 mm)
Overall length 1.550 inches (39.4 mm) 1.169 inches (29.7 mm)
Typical firearm Revolver Semi-automatic pistol
Typical capacity 5-6 rounds 7-17+ rounds
Max. pressure (SAAMI) 17,500 psi (121 MPa) 35,000 psi (240 MPa)
Venn diagram for Differences between .38 Special and 9mm
Venn diagram comparing Differences between .38 Special and 9mm


Design and Development

The .38 Special was developed at the end of the 19th century as an improvement over the .38 Long Colt. U.S. military experience in the Philippine-American War showed the .38 Long Colt to have insufficient stopping power.[1] Smith & Wesson lengthened the case of the .38 Long Colt, increasing its powder capacity. It was originally a black powder cartridge, though smokeless powder loads became available within a year of its introduction.[1] The ".38" designation refers to the approximate diameter of the loaded brass case, while the actual bullet caliber is .357 inches.[1]

The 9mm Parabellum, also known as 9mm Luger, was developed by Georg Luger from his earlier 7.65×21mm Parabellum cartridge. By removing the bottleneck of the 7.65mm case, he created a tapered, rimless cartridge for the Luger semi-automatic pistol. The German Navy adopted the cartridge in 1904, followed by the German Army in 1908. Its use expanded significantly after World War I in numerous semi-automatic pistols and submachine guns.

Performance Characteristics

A key difference in performance is operating pressure. The 9mm Parabellum is a higher-pressure round than the .38 Special. Standard 9mm ammunition operates at pressures up to 35,000 psi, while the .38 Special is rated for a much lower 17,500 psi. This[1] contributes to the 9mm generally having higher muzzle velocity and energy than standard-pressure .38 Special loads. [4] Higher-pressure "+P" loads are available for the .38 Special, which increase its performance to a level between the .380 ACP and the 9mm Parabellum. Felt[1] recoil is subjective and depends on the firearm's weight and the specific load used, but in firearms of similar weight, the .38 Special often produces less recoil than the 9mm.

Because the 9mm is primarily used in semi-automatic pistols with detachable box magazines, firearms chambered for it typically have a much higher ammunition capacity than .38 Special revolvers, which are usually limited to five or six rounds. While[5] revolvers chambered in 9mm exist, they are less common and often require moon clips to function properly with the rimless cartridge.


References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 "wikipedia.org". Retrieved December 09, 2025.
  2. "wikipedia.org". Retrieved December 09, 2025.
  3. "steinelammo.com". Retrieved December 09, 2025.
  4. 4.0 4.1 "capitalcartridge.com". Retrieved December 09, 2025.
  5. 5.0 5.1 5.2 "opticsplanet.com". Retrieved December 09, 2025.