Crazy Idea of the Week

Good Idea or not?

  • Wow Uber-snubbie !

    Votes: 10 26.3%

  • Rangie's going to blow himself up.

    Votes: 28 73.7%
  • Total voters
    38
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Rangie

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Dec 28, 2002
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How about converting a .357Mag SP-101 to 10mm-.40S&W on clips ?

Just thinking here..... If GP-100's can be converted and still be six-shooters why not the little SP? If somebody has a GP and calipers handy, what's the thickness of the cylinder walls ?

Wild west guns has 5-shot moonclips for the .357 SP-101. I'm thinking they could be opened up a little to work with the 10mm.

The numbers--

Cylinder wall thickness on the SP-101 .70

10mm case diameter .425
.357 case diameter .379
The difference = .046 divided by 2 = .023

That leaves us with .47 cylinder walls and bolt cuts safely inbetween.

I'm thinking this would work for 10mm lite loads, not for treading into .41Mag territory.

Sound possible ?
 
I would definitely like to get my hands on a snubbie in 40 s&w been hoping somebody would make a production model for some time
 
The moon clips may work fine as is. During the early days of 10mm prior to the introduction of proper 10mm shellplates, some loading die companies recommended using their .357/.38 shellplates.

For grins, I occasionally put 10mm or .40 S&W ammo into a .357/.38 speedloader or a Bianchi Speed Strip. I then hand it to a companion and wait for their reaction.
 
The first time you shoot it, use just your right hand.
Thataway we can call you "Lefty" afterwards. :p

It would be a hoot if it was workable.
 
Hmmmm.

Dunno about 10mm. :scrutiny:

40Short'n'Weak mebbe :).

If those new nylon or whatever uberplastic that is moon clips are made for 9mm 5-shot snubbies, they might "stretch" enough to cope with 40s.

Now all you need is a new barrel and some cylinder mods.

Interesting concept. But...hmmm...do you really GAIN anything going from 357Maggie to 40? Cor-Bon 125s pull more than 1,300fps from a 2" SP101. Are you really gonna top that in terms of effectiveness, with 40s from a short tube?

Hmmm.

Better idea: cut the 357 cylinder for moons. Now it can take 38, 357 and 9mm with moon-clip reload speed.

NOW you're talkin. Cheap mod, too.
 
barrel shank

Forcing cone on my SP measures .68

Difference in bullet diameter .401-.357=.044 divided by 2 = .022

.68-.022 = .658
Dosen't sound too bad ?

Jim I know this isn't going to be a huge leap in performance over the .357Mag. I just like the concept and love clip fed revolvers.

I'm thinking the Winchester 175gr. silvertip should still do 1100fps out of the 2.25" barrel.

Daniel -thanks didn't think of that.
10mm Remington brass measures .339 at extraction groove
.357 mag Winchester brass measures .372

9mm Winchester brass measures .340 .So clips from the 9mm SP-101 should work perfectly without modification.:D

Surprised to find out 9mm cartiidges fit on the moonclips for the 610.
 
Rangie,

I suspect it is technically feasible. However, I must respectfully ask why you would want to do so? The SP-101 will safely and easily accommodate all .357 magnum and .38 Special personal defense loads – from relatively mild .38 Special FMJ/target rounds to CorBon (and other manufacturers) 158 grain, .357 magnum JHP “barn burnersâ€. The only advantage provided by the .40 S&W/10mm is a millimeter greater diameter. The ballistics of top-end .357 magnum rounds certainly are as potent as 10mm loads. Therefore, this modification could be a fine “science projectâ€, but it is unlikely to make the SP-101 a more effective defensive weapon.

Regards.
 
Let me see . . . the case diameter for the 10mm is .425", and for the .357 it's .379". The difference is .046. I don't have an SP 101 handy, but measuring the .357s I have on hand gives an average outer wall thickness of .118".

Now, could the 10mm chambers be bored on the same centers as the present .357 chambers? I'm not sure -- there isn't much clearance on the inside edge of the chambers on my revolvers. But assuming they could, then the outer wall thickness would be reduced to .095".

And that assumes my .357's are representative of the smaller SP 101.

Hey, why don't we ask Ruger? Maybe they'd be interested in making an SP 101 in 10mm, if it's feasible?
 
You'll probably blow up but do it anyway, I wanna see the KB thread and pics. :D
 
Sounds like someone with waaay too much time and money on their hands. I liked the idea of modifying a .357 to take both .38 and 9mm. Care to expand?
 
Everyone worries about cylinder wall thickness, but I think how much forcing cone is left is really more often the problem...
 
The 10mm case rim is the same diameter as the .357 case rim so there shouldn't be an issue with having to make a new cylinder with chambers away from the star. If the .357 fits then so will the 10mm.

The forcing cone is definitly a concern. I don't have the expertise to know how thin is too thin for this mod. But IF the SP is as overbuilt as it's big brother it's allready been done. With the same being true for the cylinder walls.

Rugers are regarded as overbuilt and I wouldn't even be thinking about this in a J-frame or Taurus.

Ruger could make this. Ruger could sell this, and lots of them. But stagnation seems to be the name of the game for them.

S&W could do it in a K-frame, if needed with a titanium cylinder like the 646.

Taurus could just make one from scratch. Which is probably the most likely factory option.
 
Fanatic...

"Person who redoubles his efforts after losing sight of his goals."

Other than the novelty value, I'm not sure what you would gain by your efforts.

If you want a thicker bullet than 357, Taurus makes snubbies in 41 Mag, 44 Spl, and 45 Colt.

If you are really stuck on the 10mm/40 Smurf & Wimpy idea, your cheapest conversion would be the Taurus 41 Mag. This way you are already starting with a cylinder wall thickness that will handle the cartridge, and the bore diameter is pretty close, so you would have plenty of room for a custom barrel.
 
Reminds me a little of the Porsche with the Volkswagen motor
Click to expand...

If the Porsches in question were 914 (4cyl version), 356, or 912, then the Volkswagen motor would be very similar, if not identical (parts do interchange). There was a lot of sharing betwen the two companies back then. Drop a VW Type 1 (Beetle) engine into a 356 and the average person wouldn't know the difference. Same goes for the 914 or 912 to VW Type 4 swap. Outside of those three models, I don't know of any Porsches that would accept a VW engine without major mods. Maybe a 924 since it was mostly VW to begin with...

Sorry for the thread drift.

Chris
 
If you are really stuck on the 10mm/40 Smurf & Wimpy idea, your cheapest conversion would be the Taurus 41 Mag. This way you are already starting with a cylinder wall thickness that will handle the cartridge, and the bore diameter is pretty close, so you would have plenty of room for a custom barrel.

Of course if you're really going to do that, why not get a Taurus 41 and load it with 41mag bullets? Radical idea I know.
 
Rangie:

Let me know when you have this modified gun ready to shoot. I want to be at least 500 yds. behind you:what:
 
41 Mag

Hi Rabbi,

That was kind of my point.

I as trying to think of any possible reason beyond pure novelty for making such a conversion. I have nothing against novelty guns, mind you. I'm just curious if this conversion is supposed to serve a purpose beyond sheer curiosity.

Smith makes/used to make a 610 Hunter model chambered for the 10mm and capable of firing 40. It was all set up for moon clips the the rest. The down side was its not exactly a pocket gun.
 
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