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Old-style SP101 in .22 - Convert to .22 Mag?

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sp101 22lr
8K views 14 replies 8 participants last post by  DenStinett 
#1 ·
I stopped by a local LGS and range today and found this SP101 in .22. It has the box and was much cheaper than they're priced on GB ($400 versus $699, but unsold, on GB). So, I picked it up. It's been fired quite a bit but not abused. It took about an hour to get the finish - especially the cylinder - cleaned up but it looks pretty good now. It came with el-cheapo grip inserts but I had one last Ruger (Altamont, I assume?) grip insert set left.

I tried a .22 mag round, seated backwards on a chamber, and there's plenty of room in the recessed chamber area for magnum rounds. Soooo ... I don't think the recessed chamber area would have to be opened up any for magnum rounds to fit. That said, I don't know if they would sit under the sweet spot for the firing pin. And, I also did a search here for re-chambering or reaming LR to magnum but didn't find anything. What says Ruger Forum - is this revolver suitable for a .22 Mag conversion? I know Dave Clements rechambers Bearcats (or, at least he used to) but I don't know about SP101's.

Last but not least, has anyone found a source for the uber-nice engraved grip inserts?

 
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#2 · (Edited)
GeoJammy, You should be able to use a 22 Mag reamer and rechamber all 6 holes. The firing pin should align just fine. About the only issues I know of are extraction and bore diameter. 22 Mag cases are longer than 22 LR cases so you will likely have to manually pull the spent cases the rest of the way out …. no big deal. I don't recall if Ruger used a .224" bore on these earlier 22 LR SP101s or not. Use a 7/32" drill bit shank and see if it will pass in the bore. If not, DON'T rechamber it for 22 Mag!!!!
 
#3 ·
Sorry, late to the Thread
I own one of the three SP-101s the Ruger Factory set-up in .22 wmr (the KSP-240, SN: 570-68353)
I call it my "Super" SP-101, because I have both; a .22wmr and a .22lr Cylinder for it
The Bore is almost as tight as my MkII Target
I mic'd the following:
The "Super" SP101 is 0.216"
The MkII Target is 0.216"
My Wife's SP101 (gen 2, 8 Round .22lr) 0.218"
My Super Single Six 0.219"

I had the Gunsmith reprofile the Forcing Cone while they "finished" the Chambers
It works 100% now, as both; a .22lr and .22wmr

 
#8 ·
I guess it could be done
My SP-101 came from Ruger with the wmr Cylinder .... but it wasn't finished
The Gunsmiths at Sportsman's finished it, and now it works GREAT
Mind you; you CAN NOT go back and shoot .22lr Rounds through the "NOW" wmr Cylinder
I found another .22lr Cylinder, so just like the Super Single, I can swap them in and out
 
#9 ·
There weren't a lot of those original 6 shot SPs made in 22 LR, by the way. In those days the SP-101 was all about the 357 and not a lot of interest in the 22 LR version. That has changed, immensely, of course, thus Ruger bringing the 22 LR back in the current 8 shot version. Not advising you leave yours as is, but they are not all that easy to find. Either way, enjoy.
 
#11 · (Edited)
You bet Stoble
As stated; my SP-101 (Gen 1) came to me as a .22wmr
And as it turns out, one of only three that "slipped-out" of the Factory as such
Later on, I found another SP-101 (Gen 1), stoll the Cylinder out of it, and fitted that Cylinder to my wrm Frame
Then I sent the Cylinderless Frame back to Ruger, to have another .22lr Cylinder fit to IT
Problem was, Ruger couldn't come-up with a Cylinder for it, so they sent us a brand new Gen 2, 8 shoot to replace the one I sent them
I believe it cost us about $160.00 after all was send and done
Would I do it again ? yeah maybe, but I'd go about it a bit different

Just so happens, there's a Gen 1, Full Lug for sale:
 
#12 ·
The problem with the 22LR/22WMR is that the actual chamber is a larger diameter than the 22LR. There is enough diameter difference that it is easily seen with the naked eye by looking at both cartridges side by side. The 22LR will more than likely fire in the chamber, but it is mostly a single shot....needing the fired brass to be extracted by hand with a brass rod usually. And then you will notice the split case from the 22LR.....

And the reason for the forcing cone cleanup....that allows the slightly larger 22WR bullet to "ease" into the slightly smaller bore of the 22LR. The cylinder gap also allows any "extra" pressures to safely exit without problem.

Here is a good write up on the non-WMR 22 rimfire versions of ammunition.

https://www.chuckhawks.com/22_rimfire_cartridges.htm
 
#13 ·
;
The problem with the 22LR/22WMR is that the actual chamber is a larger diameter than the 22LR. There is enough diameter difference that it is easily seen with the naked eye by looking at both cartridges side by side. The 22LR will more than likely fire in the chamber, but it is mostly a single shot....needing the fired brass to be extracted by hand with a brass rod usually. And then you will notice the split case from the 22LR.....
Thanks Bubba, yeah, I get that
BUT .... I don't shoot .22lr Rounds thru a .22wmr Cylinder, I shoot .22wmr Rounds thru a wmr Cylinder
And I don't shoot .22wmr Rounds thru a .22lr Cylinder, I shoot .22lr Rounds thru a .22lr Cylinder
YES, two different Cylinders
Two Factory SP-101 Cylinders, fit to the same SP-101 Frame, kinda like a Super Single Six
My "Super" SP-101:


Yes, I know:
1) it's a PITA to switch them out, and no, it's not as easy as with a SSS, I get that
2) that I committed a "Hate Crime" by tampering with one of only THREE Ruger Factory SP-101s that THEY built in .22wmr, and the only Half Lug one ta-boot .... yeah, I get THAT too !
Well .... it's too late now ! ! !

But be honest .... Y'all wish this was YOUR Revolver, not mine ! ? !
 
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#14 ·
DenStinett, sorry I didn't make my reply clearer. I wasn't actually replying to what you did, or you at all. I was replying to Stoble, in that he was thinking they were more like the 38 Spec/357 Mag cartridges.

I actually think you did something pretty cool with your revolver, and it is YOUR revolver.....who cares what you did.....it is yours. Even if it was a collectors item or such, still yours to do with what you want.
 
#15 ·
Copy that .... My BAD :-[
Yeah, I can see how someone, unfamiliar with their differences, could think that they "should be" as interchangeable as .38sp and .357mag or .44sp and .44mag

And OH .... thanks for the support
Yeah, the Super SP-101 IS pretty cool ;-)
 
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