10MM Magnum

[475/480]

 I just heard from a friend of mine that owns a full Custom 10MM Magnum revolver (Ruger GP100) . This Christian brother is going to let me have the gun for the next 4-6 weeks and I will work up loads for him .Hey what are friends for .
When I get the gun I will post pics of the gun and data as I am able to work up loads.I have Nosler 135,150,180 gr HP's and 3 cast bullet moulds , 190gr LFNGC and 215 gr WFNGC and a Lee 175gr TCPB mould.
Thank the LORD, I have seen pics of this gun and it looks sweeeeet  .
Sean

[sqlbullet]

Holey Schnikeys...An SP101 in 10mm Magnum.  Talk about your ideal belly gun :-)

Anxious to see pictures of this one.  And curious who did the custom build?

[The_Shadow]

Be careful, as the converted SP101 (originally for 357 and bored out) may not handle full potential 10mm Magnums.
I have some Accurate Arms data for the 10mm magnum in a PDF file should you need a copy.

[475/480]

Be careful, as the converted SP101 (originally for 357 and bored out) may not handle full potential 10mm Magnums.
I have some Accurate Arms data for the 10mm magnum in a PDF file should you need a copy.

Yes and this conversion was done on a NEW 5 shot cylinder built from scratch----- NOT a rebored 6 shot.
I found John Taffins old 10 MM Mag data. If you have something different please email me a copy.

Thanks,
Sean

[The_Shadow]

Glad to hear of the 5 shot cylinder that should be much stronger...I sent you the pdf file via e-mail.
Good luck!
Wade

[475/480]

Anxious to see pictures of this one.  And curious who did the custom build?
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Gary Reeder out of Flagstaff,Az did the build.
I think it is his Skorpion series, with special full moon clips.
I hope to have the gun by friday this week.

Sean

[sqlbullet]

Gary Reeder out of Flagstaff,Az did the build.
I think it is his Skorpion series, with special full moon clips.
I hope to have the gun by friday this week.

Sean

Hearing that it is a Gary Reeder calms my fears about 10mm Mag and SP101 a good bit.  I have heard many good things about his work.

[Danimal]

Please post pics once the gun is in your possession. Thanks.

[DM1906]

That sounds like a lot of fun.  However, there a few caveats with this cartridge.  Originally and officially, it is NOT a "10mm" bullet diameter.  You need to either have the machine report or measure.  The 10mm AMT Mag is originally .397" bullet dia.  This means, if the bore is original design, .400" and .401" bullets may not be friendly.  If you load original 10mm Mag bullets (at .397/8"), and the bore is current 10mm Auto, performance will suffer, and lead bullets will be abysmal and messy.  Just suggesting you verify what you have is what you think you have.  If there's any doubt, measure.  This round was originally developed for the Automag pistol, and not much original data is available for it.  1992 was a long time ago, and not much has been done with it since.  It is recommend to use small RIFLE primers, for all but the lightest of loads with small bullets.  Larger bullets (180+) should see much slower/magnum powders and full C.O.L. (1.550", +-.003").  That's a lot of case volume for fast powders.  Also verify the headspace is very tight, with moon clips or rimmed cases being the preferred method, with open case head (closed would be better).  The original design spec (NON SAAMI) was a 220 gr. heavy jacketed bullet at near 1400 FPS through a 6" barrel.  Have fun with it.  I know I would!

[DM1906]

Gary Reeder out of Flagstaff,Az did the build.
I think it is his Skorpion series, with special full moon clips.
I hope to have the gun by friday this week.

Sean

Hearing that it is a Gary Reeder calms my fears about 10mm Mag and SP101 a good bit.  I have heard many good things about his work.

I agree, but the SP101 wouldn't be my first choice.  Maybe a BH or RH.  Not that I would eliminate the 101 as a candidate, but would consider a lot of other platforms before it.

[475/480]

DM1906 - I am not sure about some of your info?
**John Taffin has a COMPLETE write-up on his website on the IAI- 10MM Magnum - He used Starline brass many years ago - LARGE pistol primers. ALL jacketed bullets .400--ALL cast bullets .401.
The custom 5 shot  GP100 cylinder is 1.770" +/-. I will keep my COL under that.

Sean

[DM1906]

DM1906 - I am not sure about some of your info?
**John Taffin has a COMPLETE write-up on his website on the IAI- 10MM Magnum - He used Starline brass many years ago - LARGE pistol primers. ALL jacketed bullets .400--ALL cast bullets .401.
The custom 5 shot  SP101 cylinder is 1.770" +/-. I will keep my COL under that.

Sean

No disagreement.  As I said, 1992 was a long time ago.  Any differences from what I posted are probably wildcat variations of a wildcat, which isn't uncommon with obsolete testbeds.  The large pistol primer is a surprise, though.  Perhaps it is not intended for full original pressure (I certainly wouldn't entertain the notion).  The cylinder length isn't necessarily the C.O.L., and can be dangerous if assumed so.  For example, the SP101 cylinder was originally designed and intended for use with cartridges of no more than 1.590".  The distance between bullet point and forcing cone is by design.  Pressure rise and projectile acceleration can be a critical factor, and almost always is as the pressures and velocities increase, coupled with a possible tighter bore.  IAI purchased AMT much after the development of the 10mm Mag, so there may have been some significant design modifications I'm not aware of.  Just suggesting verification, that's all.

I have read and followed Taffins's writings.  He's good, but as with any of the others, I don't agree entirely with his methods, assumed facts, and/or conclusions.  Not to discredit his article, in any way.  He is as thorough as any, often more.  His test was with an IAI pistol, not the original AMT, so there may be significant changes, or none he was aware of.  I don't know, he didn't specify, the article isn't dated and I don't remember when I first read it (at first release).  You are using a completely different platform, which may present some significant differences when comparing your experience to his data.  Just suggesting caution and verification of assumed data, as with any "new" cartridge (especially one with such potential), nothing more.

[Vice]

Sounds like and interesting and fun project.   Can't wait to hear the results.

[Yondering]

Be careful, as the converted SP101 (originally for 357 and bored out) may not handle full potential 10mm Magnums.
I have some Accurate Arms data for the 10mm magnum in a PDF file should you need a copy.

Yes and this conversion was done on a NEW 5 shot cylinder built from scratch----- NOT a rebored 6 shot.
I found John Taffins old 10 MM Mag data. If you have something different please email me a copy.

Thanks,
Sean

Maybe you mean a GP100, not an SP101? The SP101 is originally a 5 shot in 357, as sold by Ruger. This is the small short-barrel pocket pistol, like  a J-frame S&W. The GP100 is the larger 6-shot 357, like a S&W 686. I've heard of GP100's converted to 10mm, but not the SP101.

[475/480]

  You are correct. It is a GP100. I have not got it yet ,hopefully SOON.

Sean


Maybe you mean a GP100, not an SP101? The SP101 is originally a 5 shot in 357, as sold by Ruger. This is the small short-barrel pocket pistol, like  a J-frame S&W. The GP100 is the larger 6-shot 357, like a S&W 686. I've heard of GP100's converted to 10mm, but not the SP101.
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