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10mm Auto

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10mm Auto
10mm Auto jacketed flat point cartridge
Place of originUnited States/Sweden
Service history
Used by
Production history
Parent case.30 Remington[5][6]
Case type
Bullet diameter
  • C.I.P.: 10.16 mm (0.400 in)[7]
  • SAAMI: .4005 in (10.17 mm)[8]
Neck diameter
  • C.I.P.: 10.74 mm (0.423 in)[7]
  • SAAMI: .423 in (10.7 mm)[8]
Base diameter
  • C.I.P.: 10.80 mm (0.425 in)[7]
  • SAAMI: .425 in (10.8 mm)[8]
Rim diameter
  • C.I.P.: 10.80 mm (0.425 in)[7]
  • SAAMI: .425 in (10.8 mm)[8]
Rim thickness
  • C.I.P.: 1.40 mm (0.055 in)[7]
  • SAAMI: .055 in (1.4 mm)[8]
Case length
  • C.I.P.: 25.20 mm (0.992 in)[7]
  • SAAMI: .992 in (25.2 mm)[8]
Overall length
  • C.I.P.: 32.00 mm (1.260 in)[7]
  • SAAMI: 1.260 in (32.0 mm)[8]
Case capacity1.56 cm3 (24.1 gr H2O)
Rifling twist406.40 mm (1 in 16 inches)[7][8]
Primer typeLarge pistol
Maximum pressure (C.I.P.)230 MPa (33,000 psi)[9]
Maximum pressure (SAAMI)37,500 psi (259 MPa)[10]
Ballistic performance
Bullet mass/type Velocity Energy
175 gr (11 g) STHP Winchester 1,290 ft/s (390 m/s) 649 ft⋅lbf (880 J)
180 gr (12 g) FMJ Federal 1,300 ft/s (400 m/s) 708 ft⋅lbf (960 J)
77 gr (5 g) RBCD TFSP 2,420 ft/s (740 m/s) 1,001 ft⋅lbf (1,357 J)
155 gr (10 g) Underwood XTP-JHP 1,500 ft/s (460 m/s) 775 ft⋅lbf (1,051 J)
155 gr (10 g) Underwood FMJ-FN 1,500 ft/s (460 m/s) 775 ft⋅lbf (1,051 J)
Test barrel length: 117 millimetres (4.6 inches)[11]
Source(s): Underwood Ammunition XTP-JHP

Underwood Ammunition FMJ-FN

RBCD Performance Plus Ammunition

The 10mm Auto (also known as the 10×25mm, official C.I.P. nomenclature: 10 mm Auto,[7] official SAAMI nomenclature: 10mm Automatic)[8] is a powerful and versatile semi-automatic pistol cartridge introduced in 1983. Its design was adopted and later produced by ammunition manufacturer FFV Norma AB of Åmotfors, Sweden.[12]

Although it was selected for service by the Federal Bureau of Investigation (FBI) in 1989 in the aftermath of the 1986 FBI Miami shootout, the cartridge was later decommissioned (except by the Hostage Rescue Team and Special Weapons and Tactics Teams) after their Firearms Training Unit eventually concluded that its recoil was too excessive for training average agents and police officers,[12] and that the pistols chambered for the cartridge were too large to grip well for some small-handed individuals. These issues led to the creation of and following replacement by a shorter version of the 10mm that exists today as the .40 S&W, and while the 10mm never attained the mainstream success of this compact variant, there is still an enthusiastic group of supporters and users, and as of 2007, in recent years it has started to grow again in popularity.[13]


The Bren Ten (left) and Smith & Wesson Model 610 Classic (right), 1983.

When FFV Norma AB (now Norma Precision AB) designed the cartridge at the behest of Dornaus & Dixon Enterprises, Inc. for their Bren Ten pistol (a newly developed handgun with a design inspired by the CZ 75), the company decided to increase the power over Jeff Cooper's original concept. The resulting cartridge—which was introduced in 1983 and produced since—is very powerful, retaining the flat trajectory and high energy of a magnum revolver cartridge in a relatively short, versatile rimless cartridge for a semi-automatic pistol.[12]

One of the first issues with its early acceptance as the result of quality problems as a result of rushed production to meet numerous (some even defaulted) pre-orders of the pistol it was originally—as well as then being only—chambered for: the Bren Ten.[14] An example is the peculiar circumstances surrounding the pistol's distribution at its primary release, leading to a number of initial Bren Tens sent to dealers and customers without magazines (the magazines themselves had complications).[15] The relatively high price of the Bren Ten compared to other pistols of the time (manufacturer's suggested retail price was $500 in 1986, the equivalent of $1,200 United States dollars in 2021[16]) was another factor in its demise, and the company was eventually forced to declare bankruptcy, ceasing operations in 1986 after only three years of inconsistent, substandard production. Had it not been for Colt making the unexpected decision in 1987 to bring out their Delta Elite pistol (a 10mm Auto version of the M1911) and later, the FBI's adoption of the caliber in 1989, the cartridge might have sunk into obsolescence, becoming an obscure footnote in firearms history.[17]

Colt Delta Elite

Due to media exposure in the television series Miami Vice, where one of the lead protagonists had used the pistol as his primary signature weapon, demand for the Bren Ten increased after manufacturing ceased. In the succeeding five years, prices on the Standard Model rose to in excess of U.S. $1,400, and original magazines were selling for over U.S. $150.[18][19]

The Federal Bureau of Investigation briefly field-tested the 10mm Auto using a M1911 pistol and a Thompson Model 1928[20] submachine gun before adopting the Smith & Wesson Model 1076 in 1990; a short-barreled version of the Model 1026 with its slide-mounted decock/firing pin block safety supplanted by only a frame-mounted decocker. A contract was signed with Heckler & Koch to produce a quantity of the specialized MP5 utilizing the cartridge, designated MP5/10 for use by their Hostage Rescue Team and Special Weapons and Tactics Teams. Since 1994, both units still field the weapon and caliber to this day.[1][2]

During testing of the caliber in 1988, it was decided that the full-power commercial load of the 10mm Auto was the best available semi-automatic pistol cartridge for law enforcement usage, but it produced excessive recoil for most agents. Thereafter, experiments were carried out, and a specification for reduced-recoil ammunition was created. The requirement was later submitted to Federal Premium Ammunition for production and further review. This became known as the "10mm Lite", or "10mm FBI" load, or attenuated 10mm, remaining common from various manufacturers today. With some pistol reliability problems increasing in this lighter load,[19] Smith & Wesson observed that a version of the 10mm case reduced to 22 millimeters in length from the original 25 mm could be made with the retained performance parameters of the "10mm Lite". This altered cartridge was named the .40 Smith & Wesson. The shorter case allowed use in pistols designed with similar dimensions to those chambered in 9×19mm Parabellum, with the advantage that smaller-handed shooters could now have smaller-frame semi-automatic handguns with near—or in some cases, exact—10mm performance. Colloquially called the "Forty Cal" and other synonyms, this innovation since became a common handgun cartridge among law enforcement agencies and civilians in the United States, while the parent 10mm Auto remains fairly popular.[12]

In 2015, SIG Sauer entered the 10mm marketplace with their P220 model chambered in 10mm. Ruger introduced a 10mm auto model to their popular SR1911 line in mid 2017, followed by their Blackhawk, Redhawk and 10mm GP100 Match Champion and Wiley Clapp models in 2018. The Springfield Armory XD-M series added a 10mm offering in late 2018.[21] In November 2021, Smith & Wesson introduced 10mm Auto models in the M&P 2.0 series.[22][23][24] In 2022 SIG released the 10mm Auto P320-XTEN in the P320 series.[25] In 2024 Taurus released their first 10mm pistol, the 10mm Auto TH10 pistol in the hammer-fired TH line.[26][27]



The 10mm Auto has 1.56 milliliter (24.1 grain H
) cartridge case capacity.

10mm Auto maximum C.I.P. cartridge dimensions. All sizes in millimeters

10mm Auto maximum CIP cartridge dimensions[7]

The common rifling twist rate for this cartridge is 406.40 mm (1 in 16 inches), 6 grooves, Ø lands = 9.91 mm (.390 in), Ø grooves = 10.17 mm (.4005 in), and land width = 3.05 mm (.120 in). A large or small pistol primer is used.[7][8]

The CIP rulings indicate a maximum pressure of 230 MPa (33,000 psi). In CIP-regulated countries, every pistol/cartridge combination is required to be proofed at 130% of this maximum CIP pressure to certify for sale to consumers.[9]

The SAAMI maximum pressure limit for the 10mm Auto is set at 37,500 psi (259 MPa).[10]



At mid-range potential, the 10mm Auto produces energy higher than an average mainstream .357 Magnum. The 10mm is slightly less powerful than the .357 Magnum with high-performing commercially-available ammunition, or hand-loaded .357 magnums, and well below standard .41 Magnum rounds. The cartridge is considered to be high-velocity, giving it a less arcing flight path upon firing (also termed "flat-shooting") relative to other handgun cartridges. More powerful loadings can basically equal the highest performing .357 Magnum loads, and retain more kinetic energy at 100 yards than the .45 ACP has at the muzzle.[12]

The 10mm outperforms the .40 S&W by 150–300 ft/s (46–91 m/s) for similar bullet weights when using available full-power loads,[28] as opposed to the "10mm FBI" level loads still found in some ammunition catalogs.[29][30] This result is due to the 10mm Auto's higher SAAMI pressure rating of 37,500 psi (259 MPa),[10] as opposed to 35,000 psi (240 MPa) for the .40 S&W,[10] and the larger case capacity, which allows the use of heavier bullets and more smokeless powder.[31]


Glock 20
Glock 29

The 10mm Auto is marketed for hunting,[32] defensive, and tactical use[33] and is one of the few semi-automatic, rimless cartridges that is legal for hunting white-tailed deer in many U.S. states.[34][35] The round makes the "Major" power factor ranking in the International Practical Shooting Confederation, even in lighter loadings.[36]

The FBI Hostage Rescue Team, Special Weapons and Tactics Teams, and various other law enforcement agencies continue to issue or authorize the use of 10mm, including: the Coconut Creek Police Department, Glasgow, Montana Police Department, Weimar Police Department,[37] and the San Francisco Bay Area Rapid Transit (BART) Police Department.[38]

In military use, the government of Denmark has issued the Glock 20 to the Slædepatruljen Sirius (Sirius Sledge Patrol) headquartered in Daneborg, Northeast Greenland.[4] The pistols were issued as a last resort defence against polar bears which the unit encounters during patrols.[39][40]

See also



  1. ^ a b "AMERICAN SPECIAL OPS – FBI HRT". Retrieved 2015-01-30.
  2. ^ a b "AMERICAN SPECIAL OPS – FBI SWAT". Retrieved 2015-01-30.
  3. ^ "FBI – Tools of the Trade – SWAT (Text Only)". Retrieved 2015-01-30.
  4. ^ a b DeMille, Dianne; Priestley, Stephen (December 2005). "Permanent Presence: Recruiting, Training, & Equipping Rangers in the Arctic". Canadian American Strategic Review. Archived from the original on 2010-07-08. Retrieved 2015-01-30.
  5. ^ Donnelly, John J. (1987). The Handloader's Manual of Cartridge Conversions. Stoeger Publishing Company. p. 941. ISBN 0-88317-136-8.
  6. ^ Howell, Ken (1995). Designing and Forming Custom Cartridges For Rifles and Handguns. Precision Shooting, Inc. p. 546. ISBN 0-9643623-0-9.
  7. ^ a b c d e f g h i j k "C.I.P. – Table of Dimensions for Cartridge and Chamber of 10 mm Auto" (PDF). Retrieved 2015-01-30.
  8. ^ a b c d e f g h i j "SAAMI – Maximum Cartridge/Minimum Chamber Drawings for 10mm Automatic" (PDF). Archived from the original (PDF) on 2015-01-30. Retrieved 2015-01-30.
  9. ^ a b "C.I.P. – List of TDCC – Tab IV – Pistol and revolver cartridges". Archived from the original on 2015-01-30. Retrieved 2015-01-30.
  10. ^ a b c d "SAAMI – Velocity & Pressure Data: Centerfire Pistol & Revolver" (PDF). Archived from the original (PDF) on 2015-03-19. Retrieved 2015-01-30.
  11. ^ "Glock 20 | G20 | 10mm Pistol | GLOCK USA". Archived from the original on 2014-12-19. Retrieved 2015-01-21.
  12. ^ a b c d e "The 10mm Auto Cartridge". BREN-TEN.com Website. Archived from the original on 2015-02-13. Retrieved 2015-01-30.
  13. ^ Ayoob, Massad (2007). The Gun Digest Book of Combat Handgunnery (6th ed.). Iola, Wisconsin: Gun Digest Books. p. 99. ISBN 978-0-89689-525-6.
  14. ^ "Dornaus & Dixon Enterprises And The Bren Ten PART 3: The Demise of Dornaus & Dixon And The Bren Ten". BREN-TEN.com Website. Retrieved 2015-01-30.
  15. ^ "The Bren Ten In Detail PART 1: Bren Ten Production Modifications". BREN-TEN.com Website. Retrieved 2015-01-30.
  16. ^ US Inflation Calculator, accessed April 4, 2021.
  17. ^ Hogg, Ian V.; Walter, John (29 August 2004). Pistols of the World. David & Charles. p. 88. ISBN 0-87349-460-1.
  18. ^ Fjestad, S. P. (1992). Blue Book of Gun Values (13th ed.). Blue Book Publications, Inc. ISBN 0-9625943-4-2.
  19. ^ a b Sweeney, Patrick (30 May 2008). The Gun Digest Book Of The Glock. Iola, Wisconsin: F+W Media. pp. 60–61. ISBN 978-1-4402-2427-0.
  20. ^ Hill, Tracie (2008). "WHAT'S NEW". The American Thompson Association newsletter. Vol. 10, no. 2nd. QTR., 2008. The American Thompson Association. p. 6. Retrieved 2015-01-30.
  21. ^ Martin, Clay (October 10, 2018). "Springfield Armory XDM 10mm – The 10 We Have Been Waiting For". gunsamerica.com. Retrieved March 20, 2020.
  22. ^ Add A Millimeter! Smith & Wesson Introduces The 10mm M&P 2.0 – First Shots
  23. ^ NEW Smith & Wesson M&P 10mm M2.0 in 4″ or 4.6″ Optics Read
  24. ^ Smith & Wesson M&P Now Goes 10mm
  25. ^ SIG Sauer unveils the P320-XTEN in 10mm, the most powerful P320 ever
  26. ^ Taurus TH10 - 10mm Double/Single Action
  27. ^ "Taurus TH10; Company's First 10mm Pistol". GunBroker.com. Retrieved 26 February 2024.
  28. ^ Ballistics information on Underwood Ammo's full-power 180 gr (12 g) 10mm load Archived 2015-01-21 at the Wayback Machine.
  29. ^ Ballistics information on Federal Premium Ammunition's "10mm Lite" style American Eagle 180 gr (12 g) 10mm load.
  30. ^ Ballistics information on Federal Premium Ammunition's American Eagle 180 gr (12 g) .40 S&W load.
  31. ^ Sweeney, Patrick (10 December 2004). The Gun Digest Book of Smith & Wesson. Iola, wisconsin: Gun Digest Books. p. 199. ISBN 1-4402-2714-4.
  32. ^ "Natchez Shooters Supplies – COR-BON 10mm Auto 200 gr Hunting Penetrator 20/box". Archived from the original on 2015-01-21. Retrieved 2015-01-30.
  33. ^ "Hornady Manufacturing Company – 10mm Auto 165 gr FTX Critical Defense". Archived from the original on 2015-01-21. Retrieved 2015-01-30.
  34. ^ Hawks, Chuck (2002). "Handgun Hunting". Archived from the original on 2011-05-01. Retrieved 2015-01-30.
  35. ^ Quinn, Jeff (2005-10-26). "Glock Model 20 10mm Auto Pistol". Retrieved 2015-01-30.
  36. ^ IPSC :: The Handgun Divisions List
  37. ^ "World Small Arms Inventory". Retrieved 2015-01-30.
  38. ^ Richman, Josh; Alund, Natalie Neysa (2014-01-22). "BART police shooting: Still unclear whether fellow officer mistook sergeant for threat". San Jose Mercury News. Retrieved 2015-01-30. Rainey said BART officers typically carry a 10 mm Glock or a .40-caliber Sig Sauer semi-automatic handgun, although some are authorized to carry other weapons.
  39. ^ "Automatics and Bolt-actions: Danish Small Arms in Greenland". Canadian American Strategic Review. May 2005. Archived from the original on 2008-09-20. Retrieved 2015-01-30. Most Danish units use 9mm automatics like the CF but the Sirius Patrol learned through hard experience that 9mms had insufficient 'stopping power' to deal with angry adult polar bears. As a result, Sirius Patrol members carry a more powerful 10mm pistols for self-defence, employing the 10mm Glock 20 automatic.
  40. ^ "Denmark Special Operations and Counterterrorist Forces – Slaedepatruljen Sirius - The Sledgepatrol Sirius (Arctic LRRP; Navy)". Special Operations.com. 2000. Archived from the original on 2011-01-13. Retrieved 2015-01-30. The weapons carried also reflect the harsh conditions. Only bolt-action rifles (M17/M53) performs reliably. The standard SIG210 Neuhausen sidearm was recently replaced by the 10mm Glock 20, as the stopping power of multiple 9mm rounds proved to be insufficient against a polar bear.