Maybe this is in the wrong section, but with the recent thread about an Italian 6904 chambered in 9 X 21 IMI, my devious mind began to wonder if any of the reloader/experimenters on this forum ever considered or tried loading 9 X 21 IMI brass to near 356 TSW (9 X 21.6) velocities/pressures.

Seems like a ready source of brass and a simple conversion.

I don't know if the cases are built the same or if the base and webbing is thick enough on the 9 X 21 case to handle higher pressures (SAAMI 52,000 psi for the 356 TSW).

Any experience or opinion?

John

Loading 9x21 brass to 356TSW levels is a Disaster waiting to happen.

If you want 356TSW performance use a firearm originally manufactured in 356TSW or one converted to handled that cartridge and use 356TSW factory ammunition or handloads.
356TSW ammunition is currently available from CorBon

Personally, I would not bother. The 9x21 is basically a civilian version of the 9x19 Parabellum for countries where civilian use of military calibers is prohibited. Ballistically, it matches the 9x19. Overall length of the loaded cartridge is the same as 9x19, it is only the case that is longer and it is not rated for pressures higher than 9x19. That's just my two cents.

If you look at performance, at least on paper, it's essentially 357Sig.

Sig .355 bullet 21.97mm (.865in)
TSW .355 bullet 21.6 (.850in)

As far as loadings 357Sig has more options so there's a broader range of speed and energy but looking at Corbon ....their 357Sig 115gr is doing 1600fps with 575ft-lbs of energy. Their 356tsw 115gr 1600fps and 650ft-lbs. .

Yes the 356 has 75ft-lbs of energy more at the same speed but this is only one load from one company. Others have different loadings which can be faster/slower, heavier/lighter...etc.

Buying a 357Sig would be easier with more options

Sent from my XT1650 using Tapatalk

Cor-Bon is currently selling 356 TSW ammo. Starline made brass for the project, and one of the members here has new 356 brass for sale.

The 9x21 brass in my experience does not have the same web integrity that the 356 brass has built into its design. I am working with another manufacturer to have 356 brass fabricated, however it won't be available until 2nd quarter of next year.

i may be wrong, but what i understand from the OP, is not load and use 9x21 to 356tsw specs and use it in a 9x21, rather load 9x21 to 356 tsw specs and use it in a 356tsw. with the scarcity of 356tsw brass and the availability of 9x21, this would probably make a (poor mans) alternative. again, this is what i understand from the OP. and if thats the case, i have no idea what the right answer may be.

Well if factory ammo is available, then I can look for a 3rd Gen 356TSW for my retirement present. Hot Dog!

I appreciate the 40S&W, and often carry a 357Sig, but factory ammo for a good 3rd Gen in 356TSW is what I prefer.

__________________
July 4, 1776 not Jan 30, 1909

You' right, stansdds. I put a post I wrote in another thread:

"There are no pressure or velocity differences between 9 luger and 9x21. In Italy 9x19 caliber is allowed only for Police and Army. So, from '85 or '86 (I dont exactly remember the year), when IMI launched his 9x21, a lot of gun brands offered guns in that caliber.
We reload 9x21 ammos with the same powder data tables in use for 9x19. So it is not nedded a different recoil spring
For italian people, 9x21 is an "escamotage" to use 9 mm diameter ammo, against a stupid government law about "war calibers".

P.S. until 2000, .45 auto as well was prohibited to civilians, in Italy. "

Actually, no...

But that is another inventive use of the case! Bravo!
(Although I'm certain the "Never Experimenters" on this forum would go ballistic (pun intended) over that extra .6mm headspace.)

What I was thinking about was "hot-rodding" the 9X21 cartridge with a shorter bullet, a little more powder, and loading it to max OAL to exceed the specs of the 9mm+P and approach the velocities/pressures of the 356tsw.
IMO it would be a simple procedure to deepen the chamber by 2mm on a spare 9mm barrel.

I thought by now, every conceivable "wildcat" had been loaded by some Dr. Kaboom.

John

I LOVE the 357Sig!

I have 357Sig barrels for my 4006 and 4006TSW pistols.
(I don't like like running those barrels in my alloy framed 40s.
Even with the max recoil spring, I don't like how hard the barrel smacks the rails).

The 9X21 idea was along the lines of getting a little more out of the 9mm family.

John

Even better!!!

Now that ammo is available, it would make more sense to ream a spare 9mm barrel to 356TSW and forget the 9X21.

John

could the re-reamed 9mm para barrel sustain the additional 356tsw pressure?? potential kaboom recipe perhaps? just asking

That is a very good question.

I had thought of that and was curious to see the difference between the two barrels.
They look the same in the chamber area from what little I've seen and I don't know what material or process S&W uses to manufacture them.
My guess is it's the same stuff.

Maybe colt_saa or another member would be kind enough to remove his 356TSW barrels and show us some pictures of the chamber ends and ideally, next to a standard 9mm chamber.

John

My guess is "the same stuff" too. Were I to rechamber one of my pistols to 9X21.5MM/.356 TSW I would not hesitate to use factory ammo or equivalent reloads in it. The .356 TSW and 9X21 were both created, for different reasons in different countries, as rule beaters. There is just no magic there. The 9X19, 9x21 and 9X21.5/356 TSW will all produce the same pressure and velocity, with the same bullet, when loaded to the same OAL. I once read results of chronographing factory .356 TSW. I may be able to find that old article somewhere around here. Anyway, I recall thinking that results didn't seem especially impressive compared with everyday 9MM +P. With all the high performance factory+P and +P+ 9MM ammo we have available today, I wonder what is to be gained by rechambering a 9MM to .356 TSW? Of course if one has a large stock of .356 factory ammo and/or cases they want to be able to use, OK I get it.

BTW, someone here must have chronographed .356 TSW from their own gun,as opposed to a gun or ammunition manufactuer's test barrel? I'd be curious as to the results......

__________________
NRA Life, COTEP 640

Yes. The case design is substantially stronger in the web than a 9mm case. That is why I am pushing for other pistol manufacturers to consider the cartridge be integrated into their product line. There is a greater margin for safety with the 356 brass than +p or +p+ 9mm luger. I have 2 1911 builds that I am currently running in 356 TSW, as well as an M&P, CZ P10C and G43. The cartridge really shines in a Pistol Caliber Carbine.

That being said, you have to understand that at the originally released specs, and what Cor-Bon has established for the velocity of their loads, guns originally designed around the 9x19 slide velocities will take a pounding unless barrel dwell time and recoil springs are properly considered.

I designed our M&P barrels around the cartridge in the anticipation of its return years ago. That is why our barrel is unique and we will be releasing our M&P barrels in 356 in 2018.

My purpose for resurrecting the 356 TSW brass is because it is a safer option than running 9x19 beyond it's safe pressure range. The 9x19 cartridge in its current form is simply at the edge of its performance envelope, especially when you try to run heavier bullets than 147 gr.

For all those interested in 356 TSW. When Corbon began testing the new load the pistols used were a 1911, some additional common offerings that were re-chambered, and some of the original Performance Center guns. The load worked fine in the 1911 and the PC guns but not in a Glock, Ruger, or SIG. We suspect the unlock time at maximum pressure is too fast without the extra lugs of a 1911 or a S&W. A 24(?) pound spring was even used at one point in the SIG but the results were unchanged. Based on my conversation with the tester it seems that somewhere over 40000 cup, certain existing slide weights, designs, and spring rates cannot manage it. This is a math problem and solvable but it takes money and time to build things. The simplest fix for it in many of the common pistols of today (Glock's, etc.) may be a compensated or ported barrel. A change in the geometry of the barrel lug and/or locking block has also been discussed. Several folks are working together on bringing this cartridge back to life. 9mm magazine capacity and 357 SIG (plus) power are an impressive combination. Testing will continue and as more is learned the info will be shared.