Posted on 06/06/2003 4:02:25 PM PDT by 45Auto
The modern beginnings of the 10MM go back to the early 1970's with the creation of the .40 G&A. At the time, there were three semi-auto cartridges of any serious consequences available, the 9MM, the .38 Super, and the .45 ACP. The idea was to come up with a cartridge that combined the best qualities of the 9MM and .45 ACP. With the creation of the new .40 semi-auto cartridge, the statement was made that "...the .40 caliber was chosen because it can be shown mathematically that it takes about this size projectile to provide the cross-sectional area to achieve adequate stopping power at reasonable pistol velocities."
There are any number of experts, men who have first hand knowledge of bullet performance in both hunting and defensive situations, who would dispute that there is any such thing as stopping power. Penetration combined with hitting vital areas seem to be much more important and the .40 G&A would certainly offer excellent penetration capabilities by combining the speed of the 9MM with the bullet weight of the .45 ACP. The larger the caliber, the better the chance of hitting vital areas. The .40, while not as good as the .45 in this respect, is certainly better than the 9mm, speaking strictly from the standpoint of the cross sectional area offered by each cartridge.
The .40 G&A was wildcatted using cut down .224 Weatherby brass and 180 grain .38-40 bullets. Chambered in a Browning Hi-Power, maximum velocities were right at 1250 feet per second. The .40 G&A went nowhere but it opened the doors for the 10MM.
Now enters the Bren Ten. In 1984, Jeff Cooper put his stamp of approval on a new semi-automatic from Dornaus & Dixon, the offspring combining some of the best features of the Czech made CZ-75 9mm with the distinct advantage of a larger hole in the barrel. The amazing thing is that Chairman Jeff took to heart a semi-auto that was not chambered in .45 ACP and was a double action semi-automatic. The new caliber was the 10mm, and the new semi-auto, while a double action, could be carried cocked-and-locked.
Cooper named the new handgun the Bren Ten, BR for the BRNO factory in Czechoslovakia and EN for the British Enfield factory. Bren Ten made a catchy name for the new 10mm. Unfortunately, the name still exists and the Bren Ten itself is no more. By 1987, Dornaus & Dixon had gone into bankruptcy.
The gun died, but the cartridge did not. Colt rescued it by chambering the Government Model, renamed the Delta Elite, and 10mm handguns have been available from Springfield Armory, IAI, LAR, Thompson/Center, Glock, Smith & Wesson with the 1006 and 1016. I can think of no other instance in history whereby the original handgun died so quickly, and yet the cartridge lived on in so many persuasions most of which are now also gone.
Loading the 10mm proved to be sufficiently easy with the use of RCBS Carbide dies. I always like to leave about one-sixteenth of an inch of the shoulder of any semi-auto bullet exposed. This works with some bullets in the Colt 10mm but loads for the Javelina must be seated with the shoulder flush with the case mouth.
Four jacketed bullets were shot extensively in the Colt and Javelina 10mms. Those bullets were Sierra's 150 and 180 grain jacketed hollow cavities, Speer's 190 FMJ, and Hornady's 200 grain FMJ. A fifth jacketed bullet, Hornady's 170 grain jacketed hollow point was used in the Javelina alone.
The 10mm proves to be quite fussy about the jacketed bullets and load combinations it is being fed. The Speer 190 would not group at all with either of the Colts with any of the loads tried. Switching to the Javelina, the same Speer 190 would shoot into less than two inches with the right load. I called Speer and they related that they too had had problems in the Colt Delta Elite and others have related that the Delta Elite is no great shakes accuracy-wise with any loads tried. Both Colt Delta Elites I used for testing the 10mm had been worked over with slide tightening, trigger jobs, etc, but had stock barrels.
Many jacketed loads proved to be exceptionally accurate in the Colt Delta Elites and the Javelina with many loads grouping under two inches or less at 25 yards when fired using the Outer's Pistol Perch as a rest. A sandbag is placed in the barrel notch of the perch and another is placed on the platform that serves as a hand rest. This proved to be the best way of using the Pistol Perch for accuracy testing.
Some excellent loads surfaced as the testing progressed. With jacketed bullets in the 180 to 200 grain category, 10.5 grains of AA#7 gave velocities in the 1100+ fps range and consistently grouped in two inches or less with both the Delta Elites and the Javelina. This same load gave the same excellent results with the RCBS #10mm-200 cast bullet in the Colt Delta Elites. Groups ran in the one and one-half inch range with velocities at 1200 feet per second. Switching to the Javelina, 11.0 grains of AA#7 gives 1281 feet per second and groups right at one-inch. An excellent practice or competition load for the 10mm with the RCBS cast bullet proved to be 5.5 grains of WW231. This load goes 1000 fps from the five-inch barrel of the Delta Elite and 1075 fps from the seven-inch barrel of the Javelina. Accuracy is so good, I would search no more. This load makes major with plenty to spare, is easy to handle and consistently groups under one and one-half inches. For a lighter cast bullet, I use the Bull-X 175 grain semi-wadcutter. The same 5.5 grains of WW231 gives velocities of 1050 in the Delta Elites and 1100 in the Javelina. Easy shooting and easily makes major for action shooting competition.
Is the 10mm a hunting pistol? With qualifications, yes it is . The qualifications are the proper ammunition and especially discretion. Pushed to the limit, the 10mm is better than the .357 Magnum but still quite a bit below the .41 Magnum. I have been using the 170 Hornady Jacketed Hollow Point and have developed a warm load of 13.0 grains of AA#7 for 1374 feet per second from the seven-inch Javelina. This should do the job on small deer without any problem. This load should also be worked up to carefully starting at around 11.0 grains.
The magazines were of plastic as I recall, maybe not the greatest material considering the way some feds toss their hardware around.
Some of the FBI guns have actually been semis, or fitted with 2-shot burst groups rather than full auto, probably not a bad idea considering the few occasions some agents get to practice. But I recall news photos of feds with *MP five and dimes* guarding the J. Edgar Hoover building at one of the periods of heightened awareness. So far as I know, noone stole the FBI headquarters, so I guess the bad guys were very, very impressed.
-archy-/-
To this old man....they sound somewhat like the scenario presented by the under appreciated .41 Rem Mag.. A wonderful round --- but not distinct enough to grab market share from the .357/.44 mag crowd..
I still have room in my garage vault - if I can be convinced I should own one....
But it will take a LOT to convince me to replace the Kimber Ultra CDP II in .45 ACP, that slips easily into Jean or Breaker pocket..

Semper Fi
Right now I have a commander sized custom meldown built up on a Springfield Armory frame and slide . Barry Mowery in Albuquerque New Mexico built that for me and Jim Clark did the meltdown. Pretty much a day to day carry unless deep conceilment is needed. Then a SIG 239 or a S&W Performance center 640 snub gets the call.
Albeit the 10MM does IMHO make a dandy common caliber for urban / city needs . Kinda like a modern version of the old 1873 winchester and the Colt SAA 44-40. May have to get such a "set" for just that reason. Wonder if Ruger's little carbines are made to take the glock magazines ?
Stay Safe RR !
If you belong to a group which uses SMGs a lot, you normally use suppressors a lot too. For that reason, subsonic .45 make a good fit.
Now that is great, you can BET I will use that in my book!!!!!
I have no idea exactly who is issued them but they seem to be the only ones seen except for the occassional AR types.
I have wondered why the two or three shot burst feature is included on so many as it is pretty easy to just get off a two or three shot burst. I personally would just as soon have a semi only.
Like you, I also have always liked the idea of pistol and carbine using the same ammo or even better the same mags and ammo. Also liked the old West combo's or their modern equivalents such as .357 mag revolver and lever action model 92 or some equivalent.
They make a 5.56mm folder now I think, to go along with their 9mm folding carbine. The 10mm sounds like a natural for that to me.
Marlin, Ruger or Winchester might take a look at 10mm also for a lever or semi "brush" hunting rifle.
Of course, you can always get a .44 mag to work in both a revolver and a rifle.
I think that is a poor trade off - giving up a proven round for a smaller or lighter piece..
Folks should really check out the super light weight and small Kimbers (and others) that are available -- and still in .45 cal.
My 60+ (lots plus) 125 lb wife with tiny hands and skinny fingers --- has NO problem at all with the 3" bbl Kimber CDP with Aluminum frame.....
In fact, when she first saw it -- she thought I had bought it for her, since she thought it looked like a "girls" gun... So small and "cute" - with an authoritative BIG voice..
Recoil is NOT objectionable -- even with the 3" bbl.. I don't know how Kimber managed that...
Semper Fi
You got about a billion-billion karma points for that selfless act.
The 1911 is just the ne plus ultra in self defense.
The Glock is a close second.
All of the above is just my experienced opinion. :)
No one has to take me seriously, and if things go wrong, don't bother to sue me, I have shallow pockets.
After listening to a friends story about the loss of a family member , I wanted to make sure it wasn't becaue they didn't have the proper tools and attitudes for self defense. I gave my Sister and Mother both a nice TiLite S&W 340 in .357 caliber with barimi grips and 2 speed loaders and gift certificates for CHL class's , the paperwork for a CHL and cashiers checks to the state of Texas for the CHL license each.
Real reason is I needed the room in my gun safe......:o).........Stay safe LibKill !
It's the double recoil spring assembly they came up with. It's still a bit of a handful for rapid fire -- but I can keep a handspan group at seven yards with it, which is what counts.
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