Someone handed my some 10MM rounds - Norma

[Lohman446]

:) I had a friend bring me a couple boxes of 10MM ammo because he had heard I had one. Norma 170 grain - advertised velocity 1300FPS on box. Handwritten price on box $16.95 (20).

I think I will save these to shoot one day when he is over.

[Dan-O]

That's a nice friend.

[RickB]

I bought a couple of boxes of Norma 200gr FMJ, mostly for nostalgia.
I was aware that ammo from the '80s was hot, sometimes even hotter than what's printed on the box, but Norma, like everyone else, apparently reduced the performance of their 10mm ammo in the '90s.
I chrono'd a box of the 200s, and I think only one round exceeded 1000fps.
My first suspicion was that the ammo had deteriorated, but a test of Norma ammo that was written-up in American Rifleman last year, resulted in an average muzzle velocity of 1048fps.

[JERRYS.]

original 10mm loads were from Norma and were: 170gr. @1,400 fps, and 200gr. @ 1,200 fps.

you might have true 10mm loads or you might have watered down loads needed for F.B.I. personnel.

it seems you have some warm loads that while aren't true 10mm powered, they are darn close.

[T. O'Heir]

"...170gr. @1,400 fps..." 1270 or 1300 FPS depending on who says it. Don't think I'd be in rush to shoot it though. Might be collector stuff one day.
The 10mm isn't as great as Cooper thought it was. Really just a slightly hotter .45 ACP. Shot a stock Delta Elite when they were new(no ammo but Norma then). Ok, but nothing special. Even the Colt Rep, who supplied the thing(very good bunch of guys those Colt Reps were), didn't seem terribly impressed. Mind you, it was at a pin shoot. A stock DE compared ok to a stock 1911A1 but not the assorted pin race guns there.

[Lohman446]

My understanding was the original idea of the 10MM was much more akin to the current .40 than what the 10MM ended up being in early production. Basically Cooper laid out some ideas that were basically a .40 caliber 200 grain bullet travelling at 1,000 FPS. This would offer a flatter shooting round with energy close to the .45.

Then the Bren Ten and Norma people got involved. Somewhere in here the case got a bit longer and the design target was 200 grains at 1200 FPS (which was substantially higher energy than the .45 of the day)

Its kind of ironic that it was the .40 that was much closer to Cooper's original thoughts than the 10MM was in the end.

The advantage of the 10MM was not supposed to be an energy gain over .45 (though it ended up being). It was intended to be a flatter shooting round carrying equivalent energy.

[RickB]

You have it right; the 10mm cartridge was intended to replace the .45 ACP as a service pistol round, not challenge the .41 Magnum for muzzle energy bragging rights.
Later in life, Cooper admitted that there's no need for a service round that hits as hard at 75 yards as .45 hits at close range, since self-defense actions don't take place at 75 yards.

[JERRYS.]

I think I remember reading Cooper saying that the ideal police cartridge was the .41 magnum police load (215gr. @ 1025 fps, not quite as magnum'esk. that's the way the 10mm was designed and loaded from the beginning.

[RickB]

It's amazing how similar are the stories of the 10mm and .41 Magnum; experienced people promote the idea of a new service cartridge, but the delivered round is so compromised that the original idea falls completely by the wayside, and we're left to debate the unintended consequences.

Because of the power of the full-magnum loads, all .41 revolvers had to be big, heavy guns. Cops prefer smaller, lighter .357s.
Because the length of the 10mm cartridge requires a big, heavy gun, cops prefer the .40.

[Lohman446]

It's amazing how similar are the stories of the 10mm and .41 Magnum; experienced people promote the idea of a new service cartridge, but the delivered round is so compromised that the original idea falls completely by the wayside, and we're left to debate the unintended consequences.

Because of the power of the full-magnum loads, all .41 revolvers had to be big, heavy guns. Cops prefer smaller, lighter .357s.
Because the length of the 10mm cartridge requires a big, heavy gun, cops prefer the .40.

What I find most interesting about it is that Cooper's original design targets involving 1000FPS 200 grains were in line with current .40s. Lengthening of the round to better fit .45 platforms allowed a higher energy design specification. If one is to take the FBI use of 10MM at face value it was this higher energy specification that hurt popularity and resulted in the "redesign" that is the super popular .40.

I personally love the 10MM for what it is and that higher energy for non-human threats is a big part of it. Still moving away from his original design seems now to have been an error for its design targets as a duty sidearm.

[RickB]

If you look at the .4" cartridges that were being wildcatted in the '60s-'70s, like the Centimeter, .40 G&A, .41 . . . what was that thing, with a rebated rim?
Anyway, the test vehicle for those rounds was the Browning Hi-Power.
If Cooper had really had his way, I think the Bren Ten would have been closer in size to the CZ75 and Hi-Power, chambered in a round more like the .40 S&W than the 10mm.
Because the Bren Ten had been initially designed around the .45 ACP cartridge, it was probably no coincidence that when a .4" round was developed for it, the new round was similar in length to the .45.

[rickmelear]

Norma, savior them

[Jim Watson]

Because the Bren Ten had been initially designed around the .45 ACP cartridge,

This is news to me, where can I see details?

[RickB]

If you can find a copy, check out Bren Ten: The Heir Apparent. It was written with the cooperation of Cooper, Tom Dornaus, and Mike Dixon.
Really excellent read on the development of the Bren, and also the 10mm and .40 S&W cartridges.
The gun originally presented to Cooper by D&D was called "CSP80" (Combat Service Pistol 1980), and was chambered in .45 ACP. After Cooper saw it, he decided it needed to be chambered in a .40" cartridge, so D&D designed that, too.

[rightside]

Just when I'm convinced I know everything.....:D

[Phil McGrath]

Gee and after all this time, I thought the real reason the 10mm came about was because the FBI couldn't/wouldn't or was too scared too ask Congress for money for new .45's after the Army had just went too the 9mm?

[rock185]

Neat to find some of that old ammo. I'm down to part of my last box of the 200 grain. I worked the Bren Ten booth at SHOT one year and once drove up to Gunsite with Tom Dornaus and Michael Dixon to shoot the pistols with Col. Cooper. When I started shooting the 10 the only factory ammo available was the Norma. I chronographed both the 170 and 200 grain in a variety of 10MM pistols. The Original Norma 170 averaged ~1300 fps and the 200 grain ~1200 fps (more often than not a little over 1200 FPS), both in 5" barrels. Norma did indeed start loading down the 10 at some point. I chronographed some of the later 200 grain ammo. I'd have to go through my old notebooks to find the exact velocity, but I recall it seemed disappointingly wimpy compared to the original load. The velocity claimed on the box did not change, but actual velocity did. BTW, one way to tell if you have the original Norma at the advertised velocity, or the later "10MM Lite" stuff is the primer. The later, more lightly loaded, Norma 10MM will have a tiny "NP" stamped on the primer. I've very occasionally run across a box of factory Norma 10MM at gun shows,etc, but it was always the later "NP" marked stuff. I didn't buy.