Munitions

10mm Auto

Also known as
  • 10 mm Auto
  • 10mm Automatic
  • 10 mm Automatic
  • 10x25mm Auto

10mm Auto is a high-pressure semi-automatic pistol cartridge developed around the Jeff Cooper and Dornaus & Dixon Bren Ten concept and first manufactured commercially by Norma Precision. It remains a commercial handgun and hunting cartridge, with SAAMI and C.I.P. standards defining the 10mm Automatic / 10 mm Auto cartridge and current manufacturers offering pistols and ammunition around it.

10mm Auto, Semi-automatic pistol cartridge, Munitions
Image source: 10MM AUTO - FMJ - 1.jpg
Profile / Specs

Profile

Origin
United States / Sweden
Type
Semi-automatic pistol cartridge
Designer
Jeff Cooper and Dornaus & Dixon development circle; commercial cartridge manufacturing by Norma Precision
Designed
Late 1970s-early 1980s cartridge and Bren Ten development
Produced
1983-present commercial production

Specifications

SAAMI designation
10mm Automatic
C.I.P. designation
10 mm Auto
Maximum average pressure
37,500 psi under SAAMI centerfire pistol/revolver standards
C.I.P. maximum pressure
2,300 bar Pmax
Bullet diameter
10.17 mm / .4005 in under C.I.P. TDCC data
Case length
25.20 mm / 0.992 in under C.I.P. TDCC data
Maximum cartridge length
32.00 mm / 1.260 in under C.I.P. TDCC data
Example defensive load
Personal Defense Punch, 10mm Auto, 200 grain jacketed hollow point, 1100 fps
Example training load
Champion Training, 10mm Auto, 180 grain full metal jacket, 1200 fps
Example hunting load
Trophy Bonded Bear Claw Handgun, 10mm Auto, 180 grain bonded soft point, 1275 fps
Compatible Handguns

10mm Auto is primarily a handgun cartridge. The catalog currently links it to the general handgun/pistol entry, while the source set documents specific 10mm Auto pistols such as the Bren Ten, Colt Delta Elite, Glock G20, and SIG Sauer P320-XTEN.

Compatible itemItem typeCompatibility evidence
Handgun/pistol, Handheld small arm / sidearm, Infantry WeaponsHandgun/pistolHandgun

Federal lists 10mm Auto among handgun calibers, and current manufacturer pages document 10mm Auto pistols chambered for the cartridge.

Sources: Shop products in Handgun today | Federal Premium, G20 Gen5 MOS | GLOCK, P320-XTEN 10mm Pistol | SIG Sauer

10mm Auto Development And Chambering Context

The cartridge is best understood through the handguns built around it: the Bren Ten launched the commercial 10mm Auto concept, Colt and Glock kept the chambering visible after Dornaus & Dixon's collapse, the FBI's late-1980s testing gave the cartridge a law-enforcement role, and current manufacturers still chamber full-size pistols for it.

  • Early development: American Rifleman traces 10mm Auto through earlier .40 G&A Magnum work before the Bren Ten and Norma cartridge entered the market in the early 1980s.
  • Bren Ten: Dornaus & Dixon designed the pistol around Norma's new 10mm cartridge, with a 200-grain, 1200 fps concept described by Forgotten Weapons.
  • FBI 10mm pistol program: OJP's NCJRS record for the 1989 FBI Law Enforcement Bulletin article says Bureau testing approved the 10mm round for new semiautomatic pistols.
  • Later chamberings: American Rifleman identifies the Colt Delta Elite and Glock G20 as important post-Bren Ten 10mm Auto pistols; GLOCK currently lists the G20 Gen5 MOS as a 10mm Auto pistol with 15-round standard magazine capacity.
  • Current commercial pistol line: SIG Sauer lists P320-XTEN models in 10mm Auto with 5-inch barrels and 10- or 15-round steel magazines depending on SKU.
Media

10mm Auto Videos

10mm Auto Images

10mm Auto, Semi-automatic pistol cartridge, Munitions - view 1
Source: Pistol calibre cartridges comparison - 9x19mm Para, .40 S&W, 10mm Auto and .45 ACP.jpg
Related Weapon Systems
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.44 Smith & Wesson Special cartridge, Revolver cartridge, MunitionsMunitions.44 Smith & Wesson Special cartridgeRevolver cartridgeThe .44 Smith & Wesson Special is a U.S. rimmed centerfire revolver cartridge developed from the .44 Russian lineage for Smith & Wesson's New Century / Triple Lock revolver context. C.I.P. lists the cartridge at 29.46 mm case length, 41.02 mm overall length, and 1000 bar Pmax, while SAAMI lists 15,500 psi MAP and recognizes 44 S&W Spl as the abbreviated name. Later .44 Remington Magnum development used the .44 Special case family as its starting point.

Sources

Shop products in 10mm Auto today | Federal PremiumPublisher: Federal Premium | Note: Supports 10mm Auto handgun-ammunition lineup details, example load names, and retail price examples. | Accessed: 2026-06-27Shop products in Handgun today | Federal PremiumPublisher: Federal Premium | Note: Supports background context that 10mm Auto is listed among Federal's popular handgun calibers. | Accessed: 2026-06-27ANSI/SAAMI Z299.3-2022 Centerfire Pistol & RevolverPublisher: Sporting Arms and Ammunition Manufacturers' Institute | Note: Supports SAAMI 10mm Automatic designation and pressure-standard context. | Accessed: 2026-06-29C.I.P. TDCC 10 mm AutoPublisher: Commission Internationale Permanente pour l'Epreuve des Armes a Feu Portatives | Note: Supports C.I.P. 10 mm Auto dimensions and Pmax pressure data. | Accessed: 2026-06-29FBI's 10mm PistolPublisher: Office of Justice Programs | Note: Supports FBI Law Enforcement Bulletin context for 1987 testing and the Bureau's approval of the 10mm round for new semiautomatic pistols. | Accessed: 2026-06-29The 10 mm Auto: History & PerformancePublisher: American Rifleman | Note: Supports development history involving Jeff Cooper, Norma, the Bren Ten, Colt Delta Elite, FBI trials, Glock G20, and broader 10mm Auto chambering context. | Accessed: 2026-06-29G20 Gen5 MOS | GLOCKPublisher: GLOCK | Note: Supports current GLOCK G20 Gen5 MOS 10mm Auto chambering and magazine-capacity context. | Accessed: 2026-06-29P320-XTEN 10mm Pistol | SIG SauerPublisher: SIG Sauer | Note: Supports current SIG Sauer P320-XTEN 10mm Auto chambering, barrel length, and magazine-package context. | Accessed: 2026-06-29Forgotten Weapons Bren TenPublisher: Forgotten Weapons | Note: Supports the selected Bren Ten video and historical context that the Bren Ten was designed around Norma's 10mm cartridge. | Accessed: 2026-06-29Category:10 mm AutoPublisher: Wikimedia Commons | Note: Supports 10 mm Auto cartridge background, including the Jeff Cooper and Norma Precision description and United States / Sweden origin context. | Accessed: 2026-06-2710MM AUTO - FMJ - 1.jpgPublisher: Wikimedia Commons | Note: Supports image provenance for a 10mm Auto cartridge photograph. | Accessed: 2026-06-27Pistol calibre cartridges comparison - 9x19mm Para, .40 S&W, 10mm Auto and .45 ACP.jpgPublisher: Wikimedia Commons | Note: Supports image provenance for a comparison photograph that includes 10mm Auto among common pistol cartridges. | Accessed: 2026-06-27