Thought of a theoretical/fantasy pistol cartridge

[Podmonkey]

Help me think of a better name for it- 7.62x21. Basically a 356 TSW case necked down to .30.
When the 7.5 FK cartridge was released I thought it was an interesting round but probably not practical for general use. Probably too punchy for military uses in sidearms or subguns/PDWs. I thought if maybe it were downloaded slightly it might become practical and it occurred to me that such a cartridge already existed- the hot subgun loads for the 7.62x25 Tokarev which the 7.5 is dimensional similar too. Then it occurred to me that while a good cartridge that perhaps was retired unjustly the Tokerev was not particularly space efficient by modern standards.
Sometime later I was reading about the unfortunately defunct 356 TSW which had 357 Sig performance, or even slightly better, in a 9mm Para sized package . The 356 TSW has a 21mm long case compared to the 19mm long Parabellum but in the 356 the bullet is seated more deeply for the same OAL, in similar fashion and for the same reason as the .38 Spc/.357 Mag.
I think its unfortunate that arbitrary rule changes in competition renders the 356 TSW obsolete before it could get off the ground as it could have made a fantastic defensive cartridge had it become established.
Then I though that a 356 TSW necked down to .30 would give the 7.5 FK lite I had been thinking of before.
Such a cartridge would have a flat trajectory for extended PDW type range out to maybe 200 yards and high penetration, good terminal effect and good controllbbilitly in addition to good size and weight efficiency. Military adoption would lead to civilian adoption where admittedly this hypothetical cartridge's advantages wouldn't matter as much. It would be a perfectly usable defensive cartridge and an awesome PCC round though. It could be a decent small game cartridge too.

 

[spat]

Help me think of a better name for it- 7.62x21. Basically a 356 TSW case necked down to .30.
When the 7.5 FK cartridge was released I thought it was an interesting round but probably not practical for general use. Probably too punchy for military uses in sidearms or subguns/PDWs. I thought if maybe it were downloaded slightly it might become practical and it occurred to me that such a cartridge already existed- the hot subgun loads for the 7.62x25 Tokarev which the 7.5 is dimensional similar too. Then it occurred to me that while a good cartridge that perhaps was retired unjustly the Tokerev was not particularly space efficient by modern standards.
Sometime later I was reading about the unfortunately defunct 356 TSW which had 357 Sig performance, or even slightly better, in a 9mm Para sized package . The 356 TSW has a 21mm long case compared to the 19mm long Parabellum but in the 356 the bullet is seated more deeply for the same OAL, in similar fashion and for the same reason as the .38 Spc/.357 Mag.
I think its unfortunate that arbitrary rule changes in competition renders the 356 TSW obsolete before it could get off the ground as it could have made a fantastic defensive cartridge had it become established.
Then I though that a 356 TSW necked down to .30 would give the 7.5 FK lite I had been thinking of before.
Such a cartridge would have a flat trajectory for extended PDW type range out to maybe 200 yards and high penetration, good terminal effect and good controllbbilitly in addition to good size and weight efficiency. Military adoption would lead to civilian adoption where admittedly this hypothetical cartridge's advantages wouldn't matter as much. It would be a perfectly usable defensive cartridge and an awesome PCC round though. It could be a decent small game cartridge too.

The 9x21 is a lot more common as the IMI version than the TSW.

I can see the attraction to making it a .30cal bottleneck, I just think you're picking the wrong parent. 9x21 IMI is a lot easier to find.

This does remind me quite a bit of the 9x25 Dillon. 1800fps with an off the shelf 115gr 9mm out of any 10mm pistol with a simple barrel change has a lot of appeal for me. I just have way to much going on to get another project going....

 

[Podmonkey]

The 9x21 is a lot more common as the IMI version than the TSW.

I can see the attraction to making it a .30cal bottleneck, I just think you're picking the wrong parent. 9x21 IMI is a lot easier to find.

This does remind me quite a bit of the 9x25 Dillon. 1800fps with an off the shelf 115gr 9mm out of any 10mm pistol with a simple barrel change has a lot of appeal for me. I just have way to much going on to get another project going....

The 9x21 IMI merely duplicates 9x19 as it operates at the same pressure and existed solely for use in jurisdictions that prohibit civilian use of so-called military calibers. 356 TSW is essentially 9mm Super with stronger brass that is thicker particularly in the case web area. It operates at very high pressures which exceeds even that of the 357 Sig. In fact when loaded with 125gr bullets the TSW exactly duplicates the performance 9f the classic. 357 Magnum police load, both launching a 125gr pill at 1450fps.
The 9x25 Dillon is still launching a 9mm bullet, is as large as the 7.5 FK with the former having neither the range nor likely the penetration of the latter.

 

[dsdmmat]

Not sure there would be an advantage, financially or performance over the cartridges available today. Maybe if you stretched it to 9x23 cartridge length. The 356 case is designed for 50K psi and offers little more case capacity over the 9x19mm cartridge (actually none when loaded with a 9mm bullet) but the 9x23 designed for 55K psi offers a lot more case capacity over the 9x19 cartridge.
The 356 cases are made of unobtainium these days, but the 9x23 is readily available.
Is this the cartridge you are basing your thoughts?

7.65×21mm Parabellum - Wikipedia

en.m.wikipedia.org

 

[Podmonkey]

Like this?

7.65×21mm Parabellum - Wikipedia

en.m.wikipedia.org

No, 356 TSW runs 50,000psi. Necking down to .30 would generate way, way more power, penetration and range than the old 7.65x21 @ 28,000 psi could manage.
The closest thing would be the rather bonkers 7.5 FK which generates as much muzzle energy as a hot .41 Magnum load. I think that is probably too much for a general issue military pistol cartridge. A .30 TSW would be closer to .30 carbine but in a much more compact package that would work well in a pistol and be an excellent subgun/PDW round. I'm thinking a 200 yard effective range is quite achievable along with good body armor penetration. Basically all the things the 5.7x28 is supposed to do but shorter and with more terminal effect.

 

[dsdmmat]

I have 3 guns chambered in 356 TSW. It is a really stout round by itself, bottle necking it would be kind of fun.

But, like I said in my previous post the brass is made of unobtainium these days. There was a bit of a resurgence in the 356 TSW a few years ago with star line agreeing to make the brass and underwood taking on loading it, but even that boat has sailed.

If I ever win the lottery I will contract with a couple of companies to make 1 million rounds of it and rechamber every 9mm gun I have into the 356TSW.

I was always interested in the 224 BOZ ever since reading about it in the 90s. 10mm cartridge necked down to .224 velocity and energy up the wazoo. The round was brutal on the guns built for it though. If I recall they had an MP5 and a 1911 chambered in it. Haven’t heard anything on that in decades. The .224 BOZ - A Forgotten PDW Cartridge

 

[Podmonkey]

I have 3 guns chambered in 356 TSW. It is a really stout round by itself, bottle necking it would be kind of fun.

But, like I said in my previous post the brass is made of unobtainium these days. There was a bit of a resurgence in the 356 TSW a few years ago with star line agreeing to make the brass and underwood taking on loading it, but even that boat has sailed.

If I ever win the lottery I will contract with a couple of companies to make 1 million rounds of it and rechamber every 9mm gun I have into the 356TSW.

I was always interested in the 224 BOZ ever since reading about it in the 90s. 10mm cartridge necked down to .224 velocity and energy up the wazoo. The round was brutal on the guns built for it though. If I recall they had an MP5 and a 1911 chambered in it. Haven’t heard anything on that in decades. The .224 BOZ - A Forgotten PDW Cartridge

I think IPSC robbed the shooting world of a fine cartridge with their arbitrary rule change. Then again had the 356 TSW seen large scale adoption we might have found 50,000 psi is a wee bit too hot for a general use pistol cartridge, who knows?
Outside of some Glock conversion kits were there any pistols besides the 3rd generation S&Ws chambered for this cartridge?
And how would you say the recoil impulse is? Manageable? Less than 10mm?

 

[dsdmmat]

No other factory guns that I know, I have a full sized S&W 3566 and 2 1911s one being compensated. Recoil is not much more than a major PF 38 super. My comped gun runs an 11 pound recoil spring and the Govt model runs an 18.5 recoil spring.

There are a couple guys on the smith forum and the 356 forum that have converted a Ruger PCC and a S&W 929 revolver.
Neither 1911 can be put in condition 2, round in chamber hammer down, because of the extended firing pins needed to keep the primers from flowing into the firing pin hole in the slide.

 

[Podmonkey]

No other factory guns that I know, I have a full sized S&W 3566 and 2 1911s one being compensated. Recoil is not much more than a major PF 38 super. My comped gun runs an 11 pound recoil spring and the Govt model runs an 18.5 recoil spring.

There are a couple guys on the smith forum and the 356 forum that have converted a Ruger PCC and a S&W 929 revolver. View attachment 267141View attachment 267143
Neither 1911 can be put in condition 2, round in chamber hammer down, because of the extended firing pins needed to keep the primers from flowing into the firing pin hole in the slide.

Imagine a Ruger PCC in my .30 TSW cartridge. You'd be obliteratIng woodchucks and rabbits at 100 yards.