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38 Super SP101?

Discussion in 'Gunsmithing and Repairs' started by JCF, Nov 21, 2006.

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  1. JCF

    JCF Member

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    I've recently been wondering about the possibility of converting a 357mag SP101 to a moonclip 38 Super... just for kicks. Does anyone have any thoughts on how difficult this conversion would be?
     
  2. 1911Tuner

    1911Tuner Moderator Emeritus

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    Super

    Doable, but don't expect sterling accuracy or top velocity. The .38 Super's bullet is 9mm, which has a nominal diameter of .355 inch. The SP101's barrel is sized to take .357 diameter bullets. If someone makes a barrel for the revolver with a correctly sized bore, it's a go. If not, you can probably expect performance in the .38 Special +p category...maybe.

    If you have a chronograph, you can find out...though it's ill-advised to fire a round in a gun not chambered for it, so apply all due caveats if you elect to try this...but the Super's semi rim will chamber and very likely headspace in the revolver's cylinder. Don't ask...:rolleyes: (Yes. I've done strange things with guns in my reckless, misspent youth.)

    This is for informational purposes only, and if you decide to fire a .38 Super round in a .357 magnum or .38 Special revolver...you're on your own.
     
  3. grendelbane

    grendelbane Member

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    The Ruger may not fire a .38 Super without the moonclip. The semi-rim of the .38 Super case is thinner than a .38 Spl or .357 magnum. The frame mounted firing pin of the Ruger may not protrude far enough to reliably set the primer off. Then again, it may. I have never tried to fire a .38 Super from an SP101.

    Most of your older Smiths probably would fire, the only Colt I have on hand has chambers too tight to take the Super, though the barrel would probably be closer to the .38 Super's dimensions.

    As far as bullet diameter goes, my Hornady manual has several .38 Super loads with .357" revolver bullets. They would work quite well for that purpose with moonclips. .38 Super pressures are pretty close to .357 mag pressures. I like the auto length pistol cases, even in a revolver. Revolver cases are way too large for moderate level loads with modern powders.
     
  4. ribbonstone

    ribbonstone Member

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    Would have a kind of odd two stage chamber throat in a converted .357...no real harm, but sending that 9mm bullet (or even a .357" diameter one) accross about .39" of .380" diameter left over .357chamber wouldnt be the best thing for accuracy. Would probably work out just fine....but at some point you just have to ask "why?".
     
  5. 1911Tuner

    1911Tuner Moderator Emeritus

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    Why

    Quote:

    >Would probably work out just fine....but at some point you just have to ask "why?"<
    ************

    Precisely. See if you can find an out-of-print Smith & Wesson revolver...the model designation escapes me at the moment...that was chambered for the 9mm and didn't require moon clips. Ream the chambers out to let the Super round headspace on the rims...may take a little customizing on the ejector star...but could likely be arranged without a lot of fuss. The revolvers are essentially 3-inch, round butt Model 13s, and would probably handle the pressures, but ask around on the S&W forum for anybody who's done the conversion to see if there are any glitches.

    The question remains. Why? .38 Super ammo availability is sometimes
    spotty, fairly expensive when you do find it, and provides no option for interchangability as with the .38/.357 revolver. You're pretty much stuck with
    one, not-so-prolific caliber that offers little advantage over the hotter .38 Specials...and gives away a good bit to the .357s round.
    Not raggin' on ya...Just curious.
     
  6. grendelbane

    grendelbane Member

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    9x23mm Winchester would be the round to use if you want HOT!

    Pressure greater than .357 magnum, though I admit I don't know how its ballistics look in a wheel gun.

    9mm J-frames have been rechambered, but I admit that I am leery of a cartridge with a slightly larger diameter case, and a MUCH higher pressure than a .357 magnum!:what:

    Still, never heard of any problems. If I ever do it, I think it will be an L-frame, however.:cool:
     
  7. ribbonstone

    ribbonstone Member

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    The rim thickenss is a little off....38sp/357mag. is listed as having a rim about .058" (it des vary in real life) and the .38super's little semi-rim is supose to run about .050". that .008 isn't a whole bunch, but it might be enough to get some trouble with firing pin strikes(esp. with the modern captive pins) Probably would work fine...leave it to you to decide if .008" of extra headspace is acceptable. If it is, then no moon clips required...no cylinder face modifications to make them run...and could still shoot .357's in the slighly modifided chamber (would have a tiny shoulder where the .38super chamber ended...and there is a risk of case splitting from the increase in diameter).

    SOME as issued .357 chambers will allow chambering of a .38super as is...chambers might be a little large and .38super factory loads often comes a little thin. Just becasue yu can jamm it in the hole don't make it wise thing to fire.

    That old no-clip S&W 9mm revolver was the 547? Anyway, the extractor asssembly was tried a couple of differnt ways...one with little spring "fingers", one for each chamber...and one with little wire loops to engage the extractor groove....the "fingers" being more common (and I don't know if the little wire loop version ever made it to real production). They weren't popular, didn't last long (and all I've seen for sale tend to the 4" square butt version...not the 3" round butt version).
     
  8. grendelbane

    grendelbane Member

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    Some Speed-Sixes and SP-101s were chambered in 9mm, with moon clips. It would be relatively easy to rechamber those to 9x23mm, and .38 Super would also fit, though the slightly larger diameter chamber base might be a little hard on brass. I don't know if they used a tighter barrel on those guns or not.

    I still want a L-frame in 9x23mm, and some day I will probably have one. I need it to go with my 9x23mm AR15. I don't have one of those either, but some day, I will.:D
     
  9. BBBBill

    BBBBill Member

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    Model 547. They were made in 3" round and 4" square versions (very rare). A unique extractor arrangement. Fingers made of beryllium copper if I recall.
     
  10. 1911Tuner

    1911Tuner Moderator Emeritus

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    547

    That's the one! I thought that was a pretty neat little wheelgun...bein' a huge fan of the 3-inch Model 13 and all...and I nearly bought one. Wish I had. There weren't many made, and I rarely see one any more. Heard of 4-inch guns, but never saw one.
     
  11. Brian Williams

    Brian Williams Moderator Emeritus

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    WHY,

    Why you ask, why do the 625's in 45ACPs rule over a 45 colt or most any other revolver in the gun games.

    A short fat case going into big large holes in a cylinder.

    Take a smaller gun and fit a short smaller diameter case and nice chamfered charge holes with a good tight moonclip. Now we are talking.

    I would love to have a totally new round made up, a true .38 caliber(not .357)about 175/190gr with a short semi rimmed case in a K frame round butt 3" barrel with moonclips.

    You ought to see what a 9mm w/moonclips does out of a S&W 60-4

    At the range of a pocket gun the "accuracy" issues of a .355 bullet out of a .357 barrel is nil.
     
    Last edited: Nov 22, 2006
  12. 1911Tuner

    1911Tuner Moderator Emeritus

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    Moon Clips

    The fastest speedloader available for a wheelgun...and I do love K-frames.:cool:
     
  13. JCF

    JCF Member

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    Why?

    Truthfully... no particular reason other than it might be fun to do it. And it would be a great conversation piece. Now what I'd really

    I've resolved to try it on an SP101...

    Will let you all know how it turns out when I'm done.
     
  14. Brian Williams

    Brian Williams Moderator Emeritus

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    If you are a reloader, just load the Super 38 with 357 cal bullets...
    Find the number of Mark Hartshorn from Pinnacle High performance, His web sight is one of the ones that moonclips.com suggests for the machining of a cylinder. Mark did the fitting of my 940 cylinder for my 642 and did the barrel swap and moonclip conversion for my S&W 65.
    Mark has told me about converting some S&W 940s to 38 super, that move takes away the problems of "sticky extraction" with 9mm's.

    I'll also bet that WildAlaska would do the same as he is also mentioned on Moonclips.com for the machining of cylinders.
     
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