9x25 Dillon
Encyclopedia
The 9x25mm Dillon, also known as the 9x25 Dillon by Dillon Precision, is a pistol wildcat cartridge
developed by employees working at Dillon Precision for use in USPSA
/IPSC
Open guns. The cartridge is made by necking down a 10mm Auto case to 9 mm.
Others have suggested that the idea behind the 9x25mm Dillon was to use the large internal case volume of the cartridge to create a large amount of gas which upon firing would be acted upon by the compensator. The 9 mm bullet was chosen because there were already several barrel manufacturers making 9 mm-based barrels for other 9mm calibers such as the .38 Super and 9x21mm.
During the mid-1990s, gunsmiths and USPSA
/IPSC
shooters were looking for ways to make the compensator
on IPSC Open guns more efficient. The compensator works by redirecting the gas from the fired cartridge to counteract the felt-recoil. At that time, the most popular cartridges competitors were using for Open guns were the .38 Super and 9x21mm.
The 9x25mm Dillon was used by several notable IPSC shooters, such as Rob Leatham
, Armt Myhre and Michael Voigt.
(24.9 grains
) H2O cartridge case capacity.
9x25mm Dillon maximum cartridge dimensions. All sizes in millimeters (mm).
Americans would define the shoulder angle at alpha/2 = 30 degrees. The common rifling
twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, Ø lands = 8.79 mm, Ø grooves = 9.02 mm, land width = 3.07 mm and the primer type
is large pistol.
According to the QuickLOAD
database the 9x25mm Dillon case can handle up to 250 MPa (36,259 psi) piezo pressure. Since there are no C.I.P. or SAAMI
limits and data sets for wildcat cartridges this data has to be regarded with caution.
The Austrian 9x25mm Super Auto G
pistol cartridge is probably the closest ballistic twin of the 9x25mm Dillon. These cartridges are both necked down 9 mm variants of the 10 mm Auto
cartridge though they dimensionally vary.
There were, however, some drawbacks to the cartridge. First was that since it was based on the 10 mm case, magazine capacity in a double-column 1911
magazine (such as a Strayer-Voigt
or STI
) was reduced by 2-4 rounds compared to a similar gun chambered in 38 Super or 9x21mm. Second was that some users of the 9x25mm Dillon were experiencing parts breakage on their guns at a much higher rate than a similar 38 Super—cracks in the compensator and slide and broken scopes.
But the biggest drawback to the cartridge, and the one that largely contributed to it falling out of favor was the enormous shock wave that was produced when the cartridge was fired. When firing the gun, the shooter could actually feel the impulse hit their face and travel up their arm. After a while, some people began to experience tendinitis in their wrists and other soreness in their wrists and arms. For a lot of people the trade-off from reduced felt recoil and a quicker second shot wasn't worth the potential damage that could be caused to their hearing and wrists.
The final event that spelled doom for the 9x25mm Dillon in competition use was when USPSA reduced the power factor necessary to make Major, from 175 to 165, which greatly reduced the internal pressures experienced in 38 Super guns shooting loads at Major power factor.
bullets, but bullets with weights as low as 80 grains were used too.
Conversions: Drop-in barrels are available as aftermarket parts for the Glock 20 and Glock 29 semi-automatic pistols. These pistols are originally chambered by Glock for parent cartridge of the 9x25 Dillon, the 10mm Auto.
Wildcat cartridge
A wildcat cartridge, or wildcat, is a custom cartridge for which ammunition and firearms are not mass produced. These cartridges are often created in order to optimize a certain performance characteristic of an existing commercial cartridge.Developing and using wildcat cartridges does not...
developed by employees working at Dillon Precision for use in USPSA
United States Practical Shooting Association
The United States Practical Shooting Association, or USPSA, is the national governing body of one form of Practical shooting in the United States, and is the US Region of the International Practical Shooting Confederation...
/IPSC
International Practical Shooting Confederation
The International Practical Shooting Confederation is a shooting sport based on the concept of practical shooting. Accuracy, power and speed are all required to achieve a maximum score.-Founding and organization:...
Open guns. The cartridge is made by necking down a 10mm Auto case to 9 mm.
History
Around 1987, Eric Harvey and Randy Shelly of Dillon Precision necked down 10mm auto brass to 9mm. Their goal was to get as much slow-burning powder in the case as possible in order to drive a 9mm bullet to the velocity needed to qualify for the IPSC Major power factor. The short-necked and steep-shouldered cartridge holds twice the powder of a .38 Super Auto case.Others have suggested that the idea behind the 9x25mm Dillon was to use the large internal case volume of the cartridge to create a large amount of gas which upon firing would be acted upon by the compensator. The 9 mm bullet was chosen because there were already several barrel manufacturers making 9 mm-based barrels for other 9mm calibers such as the .38 Super and 9x21mm.
During the mid-1990s, gunsmiths and USPSA
USPSA
USPSA may refer to:* United States Practical Shooting Association* United States Power Soccer Association...
/IPSC
International Practical Shooting Confederation
The International Practical Shooting Confederation is a shooting sport based on the concept of practical shooting. Accuracy, power and speed are all required to achieve a maximum score.-Founding and organization:...
shooters were looking for ways to make the compensator
Muzzle brake
Muzzle brakes and recoil compensators are devices that are fitted to the muzzle of a firearm or cannon to redirect propellant gases with the effect of countering both recoil of the gun and unwanted rising of the barrel during rapid fire...
on IPSC Open guns more efficient. The compensator works by redirecting the gas from the fired cartridge to counteract the felt-recoil. At that time, the most popular cartridges competitors were using for Open guns were the .38 Super and 9x21mm.
The 9x25mm Dillon was used by several notable IPSC shooters, such as Rob Leatham
Rob Leatham
Robert Jennings Leatham , also known as "TGO" is a successful professional shooter...
, Armt Myhre and Michael Voigt.
Cartridge dimensions
The 9x25mm Dillon has 1.62 mlLitre
pic|200px|right|thumb|One litre is equivalent to this cubeEach side is 10 cm1 litre water = 1 kilogram water The litre is a metric system unit of volume equal to 1 cubic decimetre , to 1,000 cubic centimetres , and to 1/1,000 cubic metre...
(24.9 grains
Grain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
) H2O cartridge case capacity.
9x25mm Dillon maximum cartridge dimensions. All sizes in millimeters (mm).
Americans would define the shoulder angle at alpha/2 = 30 degrees. The common rifling
Rifling
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...
twist rate for this cartridge is 406 mm (1 in 16 in), 6 grooves, Ø lands = 8.79 mm, Ø grooves = 9.02 mm, land width = 3.07 mm and the primer type
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
is large pistol.
According to the QuickLOAD
QuickLOAD
QuickLOAD is an internal ballistics predictor computer program for fire arms.For computations apart from other parameters* the cartridge* the used projectile * the gunbarrel length* the cartridge overall length* the used propellant...
database the 9x25mm Dillon case can handle up to 250 MPa (36,259 psi) piezo pressure. Since there are no C.I.P. or SAAMI
Saami
Saami or SAAMI can stand for:*Sami people*Sami languages*Sporting Arms and Ammunition Manufacturers' Institute...
limits and data sets for wildcat cartridges this data has to be regarded with caution.
The Austrian 9x25mm Super Auto G
9x25mm Super Auto G
The 9x25mm Super Auto G, officially known as the 9 x 25 Super Auto G by C.I.P. and unofficially also known as the 9 x 25 Super Auto Grillmeyer, is an Austrian pistol cartridge....
pistol cartridge is probably the closest ballistic twin of the 9x25mm Dillon. These cartridges are both necked down 9 mm variants of the 10 mm Auto
10 mm Auto
The 10mm Auto is a semi-automatic pistol cartridge developed by Jeff Cooper and introduced in 1983 for the Bren Ten pistol. It was initially produced by ammunitions manufacturer FFV Norma AB of Åmotfors, Sweden.Although it was selected by the F.B.I. for use in the field following the 1986 F.B.I...
cartridge though they dimensionally vary.
Performance and usage
The 9x25mm Dillon was a success in that there was a noticeable reduction in felt recoil, especially compared with comparable 38 Super IPSC Open guns. When fired the gun recoiled almost straight back into the shooter's hand rather than up and back. This resulted in competitors being able to fire their second shot more accurately in less time which increased their score. Another advantage was that the larger 9x25mm case could be loaded to 175 power factor at a lower pressure level than the 38 Super which extended the life of brass.There were, however, some drawbacks to the cartridge. First was that since it was based on the 10 mm case, magazine capacity in a double-column 1911
M1911
The M1911 is a single-action, semi-automatic, magazine-fed, and recoil-operated handgun chambered for the .45 ACP cartridge. John M. Browning designed the firearm which was the standard-issue side arm for the United States armed forces from 1911 to 1985. The M1911 is still carried by some U.S....
magazine (such as a Strayer-Voigt
Strayer Voigt Inc
Strayer-Voigt, Inc. is a manufacturer of M1911-styled modular pistols. The Strayer-Voigt system is called modular because the lower grip and trigger guard, which is made of a fiber reinforced plastic, is a separate component from the metal upper portion of the frame that comprises the dust cover...
or STI
STI International Inc
STI International, Inc. is a Texas-based company that manufactures complete M1911 pistols and parts for competition, duty and self-defense...
) was reduced by 2-4 rounds compared to a similar gun chambered in 38 Super or 9x21mm. Second was that some users of the 9x25mm Dillon were experiencing parts breakage on their guns at a much higher rate than a similar 38 Super—cracks in the compensator and slide and broken scopes.
But the biggest drawback to the cartridge, and the one that largely contributed to it falling out of favor was the enormous shock wave that was produced when the cartridge was fired. When firing the gun, the shooter could actually feel the impulse hit their face and travel up their arm. After a while, some people began to experience tendinitis in their wrists and other soreness in their wrists and arms. For a lot of people the trade-off from reduced felt recoil and a quicker second shot wasn't worth the potential damage that could be caused to their hearing and wrists.
The final event that spelled doom for the 9x25mm Dillon in competition use was when USPSA reduced the power factor necessary to make Major, from 175 to 165, which greatly reduced the internal pressures experienced in 38 Super guns shooting loads at Major power factor.
Reloading
Making the 9x25mm Dillon is fairly easy. Dillon Precision makes the necessary resizing die and reliable reloading data is easily found. Most people were using 115 grainGrain (measure)
A grain is a unit of measurement of mass that is nominally based upon the mass of a single seed of a cereal. From the Bronze Age into the Renaissance the average masses of wheat and barley grains were part of the legal definition of units of mass. However, there is no evidence of any country ever...
bullets, but bullets with weights as low as 80 grains were used too.
Commercial availability
Loaded cartridges: At least one manufacturer, DoubleTap, currently (July 2011) offers several 9x25 Dillon factory ammunition loads.Conversions: Drop-in barrels are available as aftermarket parts for the Glock 20 and Glock 29 semi-automatic pistols. These pistols are originally chambered by Glock for parent cartridge of the 9x25 Dillon, the 10mm Auto.
