The Original 10mm Ammo Made By FFV NORMA AB ·S-670 40 AMOTFORS – SWEDEN

Rewind back into the very late 70’s and early 80’s, the renowned Colonel John Dean “Jeff” Cooper, had the inspiration of a 40 caliber cartridge which would drive a 200 grain projectile @ 1000 feet per second which would translate into 444 foot pounds of energy. Seeking a semi auto platform based on the CZ-75, he discussed the concepts of gun and ammo with the new and upstart company headed up by Thomas F. Dornaus and Michael Dixon of Dornaus & Dixon Enterprises. Their first pistol was produced and chambered in 45ACP because the 10mm cartridge had not been designed as of yet. Those discussions with Col. Cooper led up to the conceptual design of the 10mm cartridge which would be based on the length of the 45ACP, so the grip would be similar in length, the cartridge overall length was set at 1.2500”. Dixon refined the case length design as being rimless, utilizing an extractor groove, taking in account thicknesses for strength for pressures generated for safety. Mike Dixon also decided on a large pistol primer (0.210”) for reliable ignition properties (later he considered this to be a mistake for fear of the ejector contacting and setting off the primer prematurely) but it was a defining factor of “Big Bore” guns.
The next step was making cartridges and bullets. Sierra Bullet Company was asked to swage their 210 grain .41 caliber JFP bullets down .40 caliber and 200 grains in weight.
Mr. John Donnelly, a friend of Mr. Copper, started with .30 Remington cases which he turned down, cut a 45 degree extractor groove and cut them to length. Mr. Donnelly proceeded to load what was said to be two boxes or 100 cartridges, dubbing them “10mm Bren” and so the 10mm was born, later Mr. Dixon changed name to 10mm Auto to be fired from the Bren Ten 10mm Auto Combat Pistol.
Mike Dixon was able to finalize external specifications; he also upped the velocity specification to 1150 feet per second, which exceeded Col. Cooper’s numbers of 1000 feet per second and Dornaus wanted the numbers low for fear of reliability. It was Mr. Dixon reasonability to find ammo makers to produce the 10mm Auto ammunition. He contacted Super Vel, “known for their high performance hollow point ammunition, but was declined. He tried Hornady Manufacturing and was turned down as well. Mr. Dixon’s contacts at Sierra Bullets put him in contact with Mr. Bert Jonsson said to be the U.S. sales manager for NORMA Ammunition AB, headquarters Amotfors, Sweden.
NORMA took on the commitment, to produce the 10mm Auto brass cases and 10mm Auto ammunition in the spring of 1983, to include pre production prototyping and new powder development including making the ammunition part of their regular product line. NORMA, utilized a 5” test barrel with “Power-Seal” rifling (same as length as the full size Bren Ten to test the new ammo. The tested velocity was said to be 1260 feet per second which equates to 704 foot pounds of energy in April of 1983 with a 200 grain Jacketed Truncated Cone bullet with a 37,000 CUP (copper units of pressure) for a 10 shot average. This placed the energy between the 158 grain .357 magnum and the 240 grain .44 magnum performance and nearly equal to the .41 magnum. Also the accuracy was an outstanding 0.45” at 50 yards…NORMA then developed an even faster 170 grain Jacketed Hollow Point rated at 1300 feet per second and 636 foot pounds energy, introduced at SHOT in 1985 in Atlanta, Georgia.
References are from the book “Bren Ten The Heir Apparent” written by Ronald A. Carrillo.
Mr. Ronald Carrillo, age 55, of Grand Junction, Colorado, died April 10, 2013. His knowledge was a great asset to the Bren Ten enthusiast as recorded in his book.
Pull-Downs of the NORMA ammunition has shown some variations in the powder charge weights in the documentations listed. Below is a list of the 10mm ammo as made by NORMA.

200gr JTC @ 1200 fps 635 Ft/Lbs Norma Ref #11001
170gr JHP @ 1300 fps 636 Ft/Lbs Norma Ref #11002
165gr JHP @ 1400 fps 719 Ft/Lbs Norma Ref #11002 (Sample labeled as 165 gr was 170gr)

NORMA Handloading data;
NORMA load data

Cartridge is from Ammo Manufacture: Norma 200 grain FMJ Truncated Cone
Ballistics Information: 10mm Auto
Muzzle Velocity: 1200 fps tested @ 1171 fps
Muzzle Energy: 639 ft. lbs
Brass Make/Headstamp: Norma – Brass (case weight w/primer 77.2 gr. / 79.2 gr)
Bullet Make/Weight/Construction/Info; Length 0.6780”/Dia. 0.4000”: 200gr Norma FMJ
Actual weigh 200.6 / 200.0 grains Crimp Diameter 0.3995”
Meplat 0.2620” Bullet base (concaved exposed lead core)
C.O.A.L.: 1.2485”
Primer: Large Pistol Primer Nickel color
Case: Diameter 0.42300” Crimp Diameter 0.4225” (tight) Length 0.9890”
Powder Description/Positive ID/Type/Charge Weight: ? NORMA R-123? 9.6 / 9.8 grains
(short rod shaped, some golden and some darker, some rod are perforated hole in the middle)

Cartridge is from Ammo Manufacture: Norma 170 grain JHP
Ballistics Information: 10mm Auto
Muzzle Velocity: 1300 fps tested @1270 fps
Muzzle Energy: 608 ft. lbs
Brass Make/Headstamp: Norma – Brass (weight 77.8 gr.)
Bullet Make/Weight/Construction/Info; Length 0.6265”/Dia. 0.4000”: 170gr Norma JHP
Actual weigh 170.0 grains (concaved base) Crimp Diameter 0.3995”
HP depth HP 0.1550” / HP dia. tapered / mouth 0.2410”
C.O.A.L.: 1.2500”
Primer: Large Pistol Primer Nickel color (NP)
Case: Diameter 0.4225” Crimp Diameter 0.4220” (tight) Length 0.9880”
Powder Description/Positive ID/Type/Charge Weight: ? NORMA R-123 ? 12.8 grains
(short rod shaped, some golden and some darker, some rod are perforated hole in the middle)

13 Responses to The Original 10mm Ammo Made By FFV NORMA AB ·S-670 40 AMOTFORS – SWEDEN

  1. Daniel E. Watters August 4, 2015 at 3:30 am #

    John Donnelly was the founder of Ballistek, a custom ammunition business. His cartridge files were the basis for his book “The Handloader’s Manual of Cartridge Conversions.”

    • Wade August 5, 2015 at 11:22 pm #

      Yes Thanks for adding the info.

  2. 4949 August 4, 2015 at 6:44 pm #

    Shadow’s pull down!

    • Wade August 5, 2015 at 11:24 pm #

      Yes, it was the basis for writing this story…

  3. Ricardo Montelban December 2, 2015 at 10:25 pm #

    None of those rounds even hit 650 foot lbs of energy at the muzzle. Its kind of dissapointing considering how everyone says the 10mm is the 41 magnums equal. Its not even the 357 magnum’s equal if you’re comparing it to original 357 magnum ammo.

    • Hunter Elliott December 2, 2015 at 11:48 pm #

      Look at Double Tap with a 180gr JHP at 1305 fps. Also, it is not all about velocity but bullet weight. If you were going to break down a wall, would you use a rock hammer you could swing fast or a sledge hammer that is swung slower. The heaviest .357 Magnum is 157gr while you can get 10mm Auto up to 220gr, all the while the 10mm is .40″ while the .357 is .358″

      • 10mmLuvr February 4, 2019 at 11:58 am #

        You can get 180g .357 mag loads… it is pretty common. Ricardo is right… the 10mm is closer to .357 mag than .41 mag. I have tested a lot of DoubleTap ammo in my G20, and their published velocities are significantly higher than what I have been able to produce. Realistically, 1150 fps for a 200g is about the max you can expect to get from a G20 4.6″ barrel.

    • Charley September 7, 2019 at 6:09 am #

      Read again. The 170 is way over 700ft lbs

  4. Comanche April 14, 2019 at 4:18 am #

    The most powerful 10 mm rounds I have tried are Underwood and Buffalo Bore!!!%🇺🇸

  5. Sfc Brad Smith April 28, 2020 at 8:09 pm #

    I have loaded 155 gr. Hpbt rds to almost 1700 ft. Per sec.!!! Wow.

  6. Joe Johnson July 23, 2020 at 2:48 pm #

    I was a fairly early adopter of the 10mm. I had a Colt Delta and a case of Norma 200 gr., Wow, was that stuff hot. I never had a chance to ghrono it but it tore the hell out of my Colt, I cracked the slide and the frame om separate occasions and after it came back the second time I sold it and got a S&W 1006 which Was happy enough with that I bought another just to modify.

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