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10mm Auto

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This article is about the ammunition cartridge. For lengths on the order of 10 millimeters, see 1 centimetre.
10mm Auto
10mm Auto FMJ cartridge
TypePistol
Place of origin Sweden
 United States
Production history
DesignerFFV Norma AB
Designed1984
Produced1984 to present
Specifications
Parent case.30 Remington[1][2]
Case typeRimless, straight
Bullet diameter10.16 mm (0.400 in)
Neck diameter10.70 mm (0.421 in)
Base diameter10.81 mm (0.426 in)
Rim diameter10.85 mm (0.427 in)
Rim thickness1.40 mm (0.055 in)
Case length25.20 mm (0.992 in)
Overall length32.00 mm (1.260 in)
Case capacity1.53 cm3 (23.6 gr H2O)
Primer typeLarge pistol
Maximum pressure258.55 MPa (37,500 psi)
Ballistic performance
Bullet mass/type Velocity Energy
150 gr (10 g) Nosler JHP 1,475 ft/s (450 m/s) 725 ft⋅lbf (983 J)
165 gr (11 g) Golden Saber HP 1,425 ft/s (434 m/s) 744 ft⋅lbf (1,009 J)
180 gr (12 g) Hornady XTP 1,350 ft/s (410 m/s) 728 ft⋅lbf (987 J)
200 gr (13 g) WFNGC HC 1,300 ft/s (400 m/s) 750 ft⋅lbf (1,020 J)
230 gr (15 g) WFNGC HC 1,120 ft/s (340 m/s) 641 ft⋅lbf (869 J)
Test barrel length: 4.6 in. For 6 inch barrel, add ~100 FPS[3]
Source(s): DoubleTap Ammunition C.I.P.[4] SAAMI[5]

The 10mm Auto (10x25mm, official C.I.P. nomenclature 10 mm Auto) is a semi-automatic pistol cartridge developed by Jeff Cooper introduced in 1983 for the Bren Ten pistol. It was initially produced by ammunition manufacturer FFV Norma AB of Åmotfors, Sweden.

Although it was selected by the FBI for use in the field, their Firearms Training Unit "concluded that its recoil was excessive in terms of training for average agent/police officer competency of use and qualification," and the pistols that chambered it were too large for some small-handed individuals.[6] These issues led to the creation and eventual adoption of a shortened version of the 10 mm that would evolve into what is today the .40 S&W.

Although respected for its performance and versatility, the 10 mm never attained the mainstream success of its downgraded variant, the .40 Smith & Wesson. It is considered a niche cartridge, with a small but enthusiastic group of supporters who often refer to the .40 S&W as the .40 Short and Weak. .

History

1983 Bren Ten 10mm, SW 610 Classic 10mm.

The 10 mm Auto cartridge was championed by famous firearms expert Jeff Cooper. It was designed to be a medium velocity pistol cartridge with better external ballistics (i.e., flatter trajectory, greater range) than the .45 ACP and greater stopping power than the 9x19mm Parabellum. When Norma designed the cartridge, at the behest of Dornaus & Dixon for their Bren Ten pistol (a strengthened variant of the CZ-75), they decided to increase the power over Cooper's original concept. The resulting cartridge, introduced in 1983, is very powerful, packing the flat trajectory and high energy of a magnum revolver cartridge into a relatively short, rimless cartridge for an automatic pistol.

The cartridge has failed to attain the same level of popularity as the 9x19mm Parabellum, .45 ACP, and the .40 S&W cartridges. This may be explained by the fact that full-powered 10mm Auto loads generate significantly more recoil and muzzle blast compared to most other common handgun cartridges. Additionally, the ballistics of milder 10mm Auto loads can be duplicated in smaller guns using the less expensive .40 S&W cartridge.

The 10 mm Auto earned a reputation for battering guns early on, largely because manufacturers attempted to simply rechamber a .45 ACP design for the 10 mm Auto.[citation needed] The .45 ACP works at a much lower pressure and velocity, and the frame and slide designed to handle the .45 ACP cannot handle the greatly increased forces of a 10 mm Auto without substantial strengthening. Later guns, such as the Glock Model 20, Glock 29 and the Smith & Wesson 1006, were built around the cartridge to help increase durability and reliability.

Another issue with early acceptance was the result of manufacturing problems with the Bren Ten. The contractor who was to manufacture the magazines was unable to deliver them on time, and as such, many early Bren Tens were shipped to dealers and customers without magazines. The relatively high price of the Bren Ten compared to other pistols (MSRP in 1986 was US$500) also contributed, and the company ceased operations in 1986, after only three years of manufacture. Had not Colt made the rather surprising decision to bring out their Delta Elite pistol, a 10mm Auto version of the Government Model, in 1987, the cartridge might have sunk into obsolescence, an obscure footnote in firearms history.

Thanks to media exposure (primarily in the television series Miami Vice), demand for the Bren Ten increased after production ceased. In the five years after production ceased, prices on the standard model rose to in excess of US$1400, and original Bren magazines were selling for over US$150 (Blue Book of Gun Values, S. P. Fjestad, 13th edition, 1992).

A Glock 20 in 10mm Auto.

The FBI briefly field tested the 10mm Auto in a 1911 frame platform as well as a 1928 Thompson type sub-machine gun before adopting the 10mm Auto round in the late 1980s along with the S&W model 1076 (a short barreled version of the 1026 with a frame-mounted decocker). During testing of a new service caliber, the FBI concluded that the full power of the load would result in undesirable recoil. The FBI then submitted a requirement for a reduced-recoil loading. This later became known as the "10 Lite", or "10 mm FBI" load. Pistol reliability problems increased with this lighter load and Smith and Wesson saw this as an invitation to create something new: a shortened version of the 10 mm. This new round was called the .40 Smith and Wesson. The .40 S&W would function in a 9 mm-sized pistol; the advantage was that smaller-handed shooters could now have a 9 mm-sized gun with near-10 mm performance. The .40 S&W has become a popular handgun caliber among law enforcement agencies in the US, while the 10mm Auto has all but disappeared outside the hands of the hobbyist. Colt, Dan Wesson Firearms, Glock, Kimber Manufacturing, Nighthawk Custom, Smith & Wesson, STI International and Tanfoglio are some of the few manufacturers that offer handguns in 10mm Auto.

A subcompact Glock 29 in 10mm Auto.

The 10 mm outperforms the .40 S&W by 200-250 ft/s for similar bullet weights when using available full power loads,[7] as opposed to the "10mm FBI" level loads still found in some ammunition catalogs.[8][9] This is due to the 10mm Auto's higher SAAMI pressure rating of 37,500 psi,[5] as opposed to 35,000 psi for the .40 S&W,[5] and the larger case capacity, which allows the use of heavier bullets and more smokeless powder.

Since its introduction, the 10mm Auto has had a reputation for accuracy which the shorter cartridge seems unable to match. Recently, it has had a small resurgence in popularity, but ammunition can still be more expensive and harder to find than the common .40 S&W. Most avid 10 mm shooters today are handloading, because the price of factory-loaded ammunition may go as high as US$37 for 25 rounds. Companies such as Remington and DoubleTap Ammunition have begun offering full power 10mm Auto loads in "reasonable" price ranges ($39–$43 for 50 rounds, with one exception of specialty rounds at $60 a box). Factory reloads are still being produced, and are carried by popular shooting ranges.

Cartridge dimensions

The 10mm Auto has 1.56 ml (24 grains H
2O) cartridge case capacity.

10mm Auto maximum C.I.P. cartridge dimensions.[4] All sizes in millimeters (mm).

The common rifling twist rate for this cartridge is 381 mm (1 in 15 in), 5 grooves, Ø lands = 9.91 mm, Ø grooves = 10.16 mm, and land width = 4.47 mm. A large pistol primer is used.

C.I.P. guidelines indicate a maximum pressure of 230 MPa (33,358 psi). In C.I.P. regulated countries, every pistol/cartridge combo is required to be proofed at 130% of this maximum C.I.P. pressure to certify for sale to consumers.

The SAAMI pressure limit for the 10mm Auto is set at 258.55 MPa (37,500 psi).[10]

Performance

The Colt 10mm Auto Delta Elite

The 10mm Auto falls between the .357 Magnum and the .41 Magnum in muzzle energy for popular loadings. With certain JHP bullets, these energy levels may produce an effect known as hydrostatic shock in living targets.[11][12][13][14][15][16] [17] The existence of this phenomenon has been questioned, however.[18][19][20]

The cartridge is considered to be high-velocity, giving it a less-curved flight path and less drop or rise above point of aim ("flat-shooting") relative to other handgun cartridges. In its lighter loadings, the 10mm Auto is an exact duplicate of the .40 S&W cartridge. More powerful loadings can equal or exceed the performance of the .357 Magnum, and retain more kinetic energy at 100 yards than the .45 ACP has at the muzzle.[21].

Some commercial loadings are as follows:

  • .357 Mag: 676 ft⋅lbf (917 J) for 180 gr (12 g) @ 1,300 ft/s (400 m/s)[22]
  • 10 mm: 750 ft⋅lbf (1,020 J) for 200 gr (13 g) @ 1,300 ft/s (400 m/s)[23]
  • .41 Mag: 938 ft⋅lbf (1,272 J) for 250 gr (16 g) @ 1,300 ft/s (400 m/s)[24]

The 10 mm load given is about maximum for SAAMI established pressure levels, while the .357 and especially the .41 Magnums are commonly handloaded to significantly higher levels than these samples. Recoil energy of full-power loads is also comparable, being 9.4, 12.4, and 15.6 ft⋅lbf (21.2 J) respectively for these loads (computed using the same powder and weight of gun). The 10mm Auto may be used for deer or other medium game at short range.

Most 10 mm handguns are not designed for long range shooting often desired in hunting; a few revolvers (using half-moon clips to adapt the cartridge) are made in this chambering, and offer another choice for hunters. Much currently manufactured 10 mm ammunition is closer in performance to the "FBI load" than the full power 10 mm; these still offer sufficient power for defense applications, yet their recoil is more comparable to the .45 ACP in similar guns. A few smaller companies offer full-power ammunition for this chambering. Due to the less common availability and higher than average cost of commercial ammunition, it is more a handloader's cartridge than most other popular auto pistol rounds. A well-stocked shooting retailer should carry 10mm Auto ammunition, though it is less likely to be stocked than more popular defensive calibers. Major ammunition companies do produce ammunition, and it is readily available through special order.Many ammunition companies and distributors now sell ammunition online,on the internet,many uncommon or harder to find calibers and loads can be found at reasonable and competitive prices.Sometimes the buyer of ammo can get the online ammo at a reduced cost when compared to traditional gunshops or chainstore retailers.This is true for the 10mm Auto.

Usage

File:Eaawitness.jpg
The Tanfoglio Force/EAA Witness steel frame 10mm Auto with Wonder Finish

The 10mm Auto is suitable for hunting medium-sized game at moderate ranges, is certainly more than adequate for defensive or tactical use, and is one of the few true semi-automatic, rimless cartridges that is legal for hunting whitetail deer in many US states.

Today, the 10mm Auto cartridge is generally used to fend off medium-sized dangerous animals, as a high-powered defensive handgun, and for hunting, especially by those who prefer the flatter carry profile and higher cartridge capacity of an automatic pistol versus a magnum revolver. It makes Major ranking in IPSC, even in lighter loadings.

Despite the FBI switching to the .40 S&W, there are still a number of law enforcement agencies that issue the 10 mm including the Albuquerque J.P.D. and the Anniston, Alabama P.D.

Synonyms

  • 10 mm Bren Ten
  • 10 mm Norma
  • 10 mm FBI
  • 10x25mm
  • The Centimeter (this name is also used to refer to a wildcat cartridge based on the 10 mm Auto, which is trademarked by Pistol Dynamics)[25]

See also

References

  1. ^ Donnelly, John J. (1987). The Handloader's Manual of Cartridge Conversions. Stoeger Publishing. p. 941. ISBN 978-0883172698. {{cite book}}: More than one of |pages= and |page= specified (help)
  2. ^ Howell, Ken (1995). Designing and Forming Custom Cartridges. Precision Shooting. p. 546. ISBN 0-9643623-0-9. {{cite book}}: More than one of |pages= and |page= specified (help)
  3. ^ "Review at DoubleTap". Archived from the original on 2009-07-20. Retrieved 2009-07-16. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  4. ^ a b "C.I.P. decisions, texts and tables - free current C.I.P. CD-ROM version download (ZIP and RAR format)". Retrieved 2008-10-17.
  5. ^ a b c SAAMI pressure specs.
  6. ^ The 10mm Auto Cartridge, quoting Shooting Times, "The Rise & Fall of the 10mm," by Dick Metcalf, November 1999.
  7. ^ Ballistics information on DoubleTap Ammo's full-power 180 gr (12 g). 10 mm load.
  8. ^ Ballistics information on Federal's "10mm Lite" style American Eagle 180 gr (12 g). 10 mm load.
  9. ^ Ballistics information on Federal's American Eagle 180 gr (12 g). .40S&W load.
  10. ^ "SAAMI Pressures". Retrieved 2007-11-29.
  11. ^ "Scientific Evidence for Hydrostatic Shock".
  12. ^ Göransson AM, Ingvar DH, Kutyna F: Remote Cerebral Effects on EEG in High-Energy Missile Trauma. The Journal of Trauma. 28(1 Supplement):S204-S205; January 1988.
  13. ^ Suneson A, Hansson HA, Seeman T: Pressure Wave Injuries to the Nervous System Caused by High Energy Missile Extremity Impact: Part I. Local and Distant Effects on the Peripheral Nervous System. A Light and Electron Microscopic Study on Pigs. The Journal of Trauma. 30(3):281-294; 1990.
  14. ^ Suneson A, Hansson HA, Seeman T: Pressure Wave Injuries to the Nervous System Caused by High Energy Missile extremity Impact: Part II. Distant Effects on the Central Nervous System. A Light and Electron Microscopic Study on Pigs. The Journal of Trauma. 30(3):295-306; 1990.
  15. ^ Wang Q, Wang Z, Zhu P, Jiang J: Alterations of the Myelin Basic Protein and Ultrastructure in the Limbic System and the Early Stage of Trauma-Related Stress Disorder in Dogs. The Journal of Trauma. 56(3): 604-610; 2004.
  16. ^ Sturtevant B, Shock Wave Effects in Biomechanics, Sadhana, 23: 579-596, 1998.
  17. ^ Courtney A, Courtney M. "Links between traumatic brain injury and ballistic pressure waves originating in the thoracic cavity and extremities. Brain Injury 21(7): 657-662, 2007" (PDF).
  18. ^ "The Shockwave Myth" (PDF). Fackler ML: Literature Review and Comment. Wound Ballistics Review Winter 1991: pp. 38-40. Retrieved 2007-04-11.
  19. ^ Patrick UW: Handgun Wounding Factors and Effectiveness. FBI Firearms training Unit, Quantico, VA. 1989.
  20. ^ MacPherson D: Bullet Penetration—Modeling the Dynamics and the Incapacitation Resulting From Wound Trauma. Ballistics Publications, El Segundo, CA, 1994.
  21. ^ Bren-Ten Website History and various specs on the 10mm Auto.
  22. ^ Doubletapammo .357 Magnum
  23. ^ Doubletapammo 10mm Auto
  24. ^ Doubletapammo .41 Magnum
  25. ^ Welcome to Pistol Dynamics.
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