10mm Auto

File:DCB Shooting Bren Ten & SW 610.jpg (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.

Quality control issues plagued early acceptance of the caliber, 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.{{cite web | url=http://www.bren-ten.com/website/id2.html | archive-url=https://web.archive.org/web/20160405195319/http://www.bren-ten.com/website/id2.html | archive-date=2016-04-05 | title=Dornaus & Dixon Enterprises And The Bren Ten PART 3: The Demise of Dornaus & Dixon And The Bren Ten | publisher=BREN-TEN.com Website | access-date=2015-01-30}} 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).{{cite web | url=http://www.bren-ten.com/website/id3.html | title=The Bren Ten In Detail PART 1: Bren Ten Production Modifications | publisher=BREN-TEN.com Website | access-date=2015-01-30}} 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[https://www.usinflationcalculator.com/ US Inflation Calculator], accessed April 4, 2021.) 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.{{cite book|last1=Hogg|first1=Ian V.|author-link1=Ian V. Hogg|last2=Walter|first2=John|title=Pistols of the World|url=https://books.google.com/books?id=okQH6zFgDtUC&pg=PA88|date=29 August 2004|publisher=David & Charles|isbn=0-87349-460-1|page=88}}

File:Var1bluede.jpg]]

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.{{Cite book |last=Fjestad |first=S. P. |year=1992 |title=Blue Book of Gun Values

|edition=13th |publisher=Blue Book Publications, Inc |isbn=0-9625943-4-2}}{{cite book|last=Sweeney|first=Patrick|author-link=Patrick Sweeney (gunsmith)|title=The Gun Digest Book Of The Glock|url=https://books.google.com/books?id=5xdZU0RJqswC&pg=PA60|date=30 May 2008|publisher=F+W Media|location=Iola, Wisconsin|isbn=978-1-4402-2427-0|pages=60–61}}

The Federal Bureau of Investigation briefly field-tested the 10mm Auto using a M1911 pistol and a Thompson Model 1928 submachine gun{{Cite magazine |last=Hill |first=Tracie |date=2008 |title=WHAT'S NEW |url=http://www.nfatoys.com/tsmg/tata/2008_q2/page00006.htm |volume=10 |issue=2nd. QTR., 2008 |magazine=The American Thompson Association newsletter |publisher= The American Thompson Association |page=6 |access-date=2015-01-30}}{{cite web | url=https://www.americanrifleman.org/content/full-power-full-auto-the-thompson-goes-metric-and-the-mp5-goes-american/ | title=An Official Journal of the NRA | Full Power/Full Auto: The Thompson Goes Metric and the MP5 Goes American }} as an "urban carbine" 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.

The 10mm cartridge was selected for Federal Bureau of Investigation use after a Wound Ballistics Seminar at the FBI Academy in September 1987, which managed to agree what a good cartridge would do, but couldn't agree if 9mm or .45 ACP could meet FBI requirements.{{Cite web |title=FBI's 10mm Pistol {{!}} Office of Justice Programs |url=https://www.ojp.gov/ncjrs/virtual-library/abstracts/fbis-10mm-pistol |access-date=2024-12-21 |website=www.ojp.gov}} In the same year, an informal test was conducted using a variety of available 9mm and .45 ACP handguns. The test indicated that only the type of 9mm round, described as "147 grain subsonic hollow point round produced by Winchester" had acceptable penetration.{{Cite journal |date=1987 |title=FBI's 1987 Handgun Evaluation |url=https://www.ojp.gov/pdffiles1/Digitization/113821NCJRS.pdf |journal=}} The test seemed inconsistent or contradictory to future observers, and it was accused of heavy .45 ACP and American handgun bias.{{Cite AV media |url=https://www.youtube.com/watch?v=Ux8A4nPJJWs |title=The FBI Said This is the Best Handgun (and Why They're Wrong) |date=2022-07-07 |last=TFB TV |access-date=2024-12-21 |via=YouTube}}

According to the latter 10mm report, it was decided: "five shots were fired in each of the 8 penetration tests, providing a total of 40 shots for each caliber or bullet type tested". The first selected was the 9mm described above. The second was a ".45 round, Remington 185 grain hollow point". The Wound Ballistic Workshop participants had a "consensus" that hollow points with "superior penetration" was what was needed.

The 10mm was picked as a "halfway" between the other two options, in terms of size. The "commercial loadings" had "high chamber pressures", which resulted in "heavy recoil" and "muzzle blast". A 180 grain hollow point bullet was "acquired and handloaded to a velocity of 950 feet per second". Later on, factory-loaded ammunition was acquired that met their requirements. During the trials, the 10mm was found to be comparable to the .45 ACP (Not surprising as the bullet weight and velocities were now so similar), but the 10mm was found to take up less space and produce shot groups on targets that were half the size.

As the FBI was adopting a 10mm cartridge closer in bullet weight and velocity to the .45 ACP, there was a need for large amounts of newly built ammunition of this type. This 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, 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. 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 and has shown a resurgence in recent years particularly among hunters.

The 10mm Auto has 1.56 milliliter (24.1 grain {{Chem|H|2|O}}) cartridge case capacity.

file:10 mm Auto.jpgs]]

10mm Auto maximum CIP cartridge dimensions

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.

The CIP rulings indicate a maximum pressure of {{Convert|230|MPa|psi|abbr=on}}. 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.

The SAAMI maximum pressure limit for the 10mm Auto is set at {{Convert|37500|psi|MPa|abbr=on}}.

At mid-range potential, the 10mm Auto produces energy higher than average .357 Magnum loads. The 10mm is slightly less powerful than the .357 Magnum with high-performing commercially-available ammunition, or hand-loaded .357 magnums, and 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 equal the highest performing .357 Magnum loads, and retain more kinetic energy at 100 yards than the .45 ACP has at the muzzle.

The 10mm outperforms the .40 S&W by {{Convert|150|-|300|ft/s|m/s|abbr=on}} for similar bullet weights when using available full-power loads,Ballistics information on Underwood Ammo's full-power {{Convert|180|gr|g|abbr=on}} [http://www.underwoodammo.com/10mmauto180grainfullmetaljacketboxof50.aspx 10mm load] {{Webarchive|url=https://web.archive.org/web/20150121060037/http://www.underwoodammo.com/10mmauto180grainfullmetaljacketboxof50.aspx |date=2015-01-21 }}. as opposed to the "10mm FBI" level loads still found in some ammunition catalogs.Ballistics information on Federal Premium Ammunition's "10mm Lite" style American Eagle {{Convert|180|gr|g|abbr=on}} [http://www.federalpremium.com/products/details/handgun.aspx?id=67 10mm load].Ballistics information on Federal Premium Ammunition's American Eagle {{Convert|180|gr|g|abbr=on}} [http://www.federalpremium.com/products/details/handgun.aspx?id=84 .40 S&W load]. This result is due to the 10mm Auto's higher SAAMI pressure rating of {{Convert|37500|psi|MPa|abbr=on}}, as opposed to {{Convert|35000|psi|MPa|abbr=on}} for the .40 S&W, and the larger case capacity, which allows the use of heavier bullets and more smokeless powder.{{cite book|last=Sweeney|first=Patrick|title=The Gun Digest Book of Smith & Wesson|url=https://books.google.com/books?id=_OtamYg8dq4C&pg=PA199|date=10 December 2004|publisher=Gun Digest Books|location=Iola, wisconsin|isbn=1-4402-2714-4|page=199}}

File:Glock 20.jpg]]

File:GLOCK 29 10mm.jpg]]

The 10mm Auto is marketed for hunting,{{Cite web |title=Natchez Shooters Supplies – COR-BON 10mm Auto 200 gr Hunting Penetrator 20/box |url=http://www.natchezss.com/product.cfm?contentID=productDetail&prodID=CBCB10200PN |access-date=2015-01-30 |archive-url=https://web.archive.org/web/20150121054947/http://www.natchezss.com/product.cfm?contentID=productDetail&prodID=CBCB10200PN |archive-date=2015-01-21 |url-status=dead }} defensive, and tactical use{{Cite web |title=Hornady Manufacturing Company – 10mm Auto 165 gr FTX Critical Defense |url=http://www.hornady.com/store/10mm-165-gr-CD/ |access-date=2015-01-30 |archive-url=https://web.archive.org/web/20150121060639/http://www.hornady.com/store/10mm-165-gr-CD/ |archive-date=2015-01-21 |url-status=dead }} and is one of the few semi-automatic, rimless cartridges that is legal for hunting white-tailed deer in many U.S. states.{{Cite web |last=Hawks |first=Chuck |year=2002

|title=Handgun Hunting |archive-url=https://web.archive.org/web/20110501015713/http://www.chuckhawks.com/handgun_hunting.htm |url=http://www.chuckhawks.com/handgun_hunting.htm

|archive-date=2011-05-01 |access-date=2015-01-30}}{{Cite web |last=Quinn |first=Jeff |date=2005-10-26 |title=Glock Model 20 10mm Auto Pistol|url=http://www.gunblast.com/Glock20.htm |access-date=2015-01-30}} The round makes the "Major" power factor ranking in the International Practical Shooting Confederation, even in lighter loadings.[http://www.ipsc.org/rules/divlistP.php IPSC :: The Handgun Divisions List]

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,{{Cite web

|title=World Small Arms Inventory |url=https://sites.google.com/site/worldinventory/ |access-date=2015-01-30}} and the San Francisco Bay Area Rapid Transit (BART) Police Department.{{Cite news |last1=Richman |first1=Josh |last2=Alund |first2=Natalie Neysa |date=2014-01-22 |title=BART police shooting: Still unclear whether fellow officer mistook sergeant for threat |url=http://www.mercurynews.com/crime-courts/ci_24971843/bart-police-shooting-still-unclear-whether-fellow-officer

|work=San Jose Mercury News |access-date=2015-01-30 |quote=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.}}

In military use, the government of Denmark has issued the Glock 20 to the Slædepatruljen Sirius (Sirius Sledge Patrol) headquartered in Daneborg, Northeast Greenland. The pistols were issued as a last resort defence against polar bears which the unit encounters during patrols.{{cite news | url=http://www.casr.ca/id-arcticviking4sb-1.htm | title=Automatics and Bolt-actions: Danish Small Arms in Greenland | publisher=Canadian American Strategic Review | date=May 2005 | access-date=2015-01-30 | archive-url=https://web.archive.org/web/20080920120203/http://www.casr.ca/id-arcticviking4sb-1.htm | archive-date=2008-09-20 | quote=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.}}{{cite web | url=http://www.specialoperations.com/Foreign/Denmark/ | title=Denmark Special Operations and Counterterrorist Forces – Slaedepatruljen Sirius - The Sledgepatrol Sirius (Arctic LRRP; Navy) | publisher=Special Operations.com | access-date=2015-01-30 | year=2000 | archive-url=https://web.archive.org/web/20110113214609/http://www.specialoperations.com/Foreign/Denmark/ | archive-date=2011-01-13 | quote=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.}}

• 9×25mm Dillon
• 10 mm caliber
• List of handgun cartridges
• Table of handgun and rifle cartridges

{{Reflist|2}}

{{Commons category}}

• [https://web.archive.org/web/20110210151806/http://thegunzone.com/brenx/40ga.html The Gun Zone – Birth of the 10mm Autopistol Cartridge]
• [https://web.archive.org/web/20150213081333/http://www.bren-ten.com/website/id7.html BREN-TEN.com Website – The 10mm Auto Cartridge]
• [https://web.archive.org/web/20131110213445/http://cheaperthandirt.com/blog/?p=32678 Cheaper Than Dirt – Cartridge of the Week, the 10mm, 10mm Auto]
• [http://the10mmautoisaliveandwell.blogspot.com/ Blogger – The 10mm Auto pistol cartridge is Alive and Well]
• [http://www.brassfetcher.com/Handguns/10mm%20Auto/10mm%20Auto.html Brass Fetcher Ballistic Testing – 10mm Auto]
• [http://www.chuckhawks.com/10mm.htm CHUCKHAWKS.COM – 10mm Auto]
• [http://www.ballistics101.com/10mm.php Ballistics 101 – 10mm Ballistics Chart]
• [http://www.ballisticsbytheinch.com/10mm.html Ballistics By The Inch – 10mm Results]
• [https://web.archive.org/web/20170820051355/http://handloads.com/loaddata/default.asp?Caliber=10%20mm&Weight=All&type=Handgun&Order=Powder&Source= Handloads.Com – 10 mm Load Data]
• [https://web.archive.org/web/20170620025703/http://www.handloads.com/misc/stoppingpower.asp?Caliber=1&Weight=All Handloads.Com – 10 mm Stopping Power]
• [http://www.gunblast.com/Glock20.htm GunBlast.com – Glock Model 20 10mm Auto Pistol]
• [http://www.gunblast.com/RKCampbell_10mm.htm GunBlast.com – The 10mm]
• [http://www.gunblast.com/SW-610.htm GunBlast.com – Smith & Wesson Brings Back the 10mm Model 610 Revolver]
• [http://www.gunblast.com/10mm.htm GunBlast.com – The 10mm Auto Pistol]
• [http://www.gunblast.com/Colt-DeltaElite.htm GunBlast.com – Colt Delta Elite 10mm Semi-Automatic Pistol]
• [http://modernfirearms.net/en/cartridge/10mm-auto-10x25/ Modern Firearms: 10mm Auto Cartridge]

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Category:10mm Auto firearms

Category:Weapons and ammunition introduced in 1983

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