I recently picked up a 3" SP101 in .38 cal only. Other than barrel lengths, it appears to be the same as my 2" .357 in every way except for the chambers and caliber marking, of course. If this is correct, does it mean I could swap out the .38 chambered cylinder for a .357 chambered cylinder and not hurt either gun?
SP101 Caliber Question
- Thread starter Reaper9
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contender
Ruger Guru
Welcome to the Forum!
I'm not an expert on the SP-101's like that,,, but if my faded memory is correct,,, the frame window dimensions are a bit shorter than the 357 versions. I don't think a cylinder swap will work.
I'm not an expert on the SP-101's like that,,, but if my faded memory is correct,,, the frame window dimensions are a bit shorter than the 357 versions. I don't think a cylinder swap will work.
Thanks for the response. I may have to break out the calipers and do some comparison measuring. I am mainly just curious about whether it can be done, since .38 Specials are about all I care to shoot in a SP101. The main thing I have learned from shooting the 3" SP101 so far is that I would like to shoot it a lot more.
Depends on the frame size. If there is an 'x' in the model number, as in KSP-831 X, it's the long frame.
The 'normal' .357 mag. cylinder will fit.
There are about 3,000 short frame .357 magnums out there but they are marked on the barrel "125 gr. only". One of those cylinders would fit a short frame gun. However, the cylinder is not marked with any identifying notes.
The long frame was introduced about Ser. No. 570-68xxx. However, short frames continued to be cast as late as 572-63xxx. So....ser. no. alone does not help much.
Terry T
The 'normal' .357 mag. cylinder will fit.
There are about 3,000 short frame .357 magnums out there but they are marked on the barrel "125 gr. only". One of those cylinders would fit a short frame gun. However, the cylinder is not marked with any identifying notes.
The long frame was introduced about Ser. No. 570-68xxx. However, short frames continued to be cast as late as 572-63xxx. So....ser. no. alone does not help much.
Terry T
contender
Ruger Guru
See,,,,,, MUCH better info from a member who does know all the little differences! Thanks Terry!
needsmostuff
Blackhawk
I think we often worry to much about .357 capability over 38 spl. I say load her up with some super 158 gr. +Ps and shoot it some .
I'm betting in that little gun that's about all the wallop your going to want.
If you want a 357 ,,buy one,,but as it is most SPs spend their whole life shooting 38 spl. anyway.
I'm betting in that little gun that's about all the wallop your going to want.
If you want a 357 ,,buy one,,but as it is most SPs spend their whole life shooting 38 spl. anyway.
Jimbo357mag
Hawkeye
You don't need to swap cylinders, just have the 38 special cylinder reamed to 357 magnum, then you can shoot both. 
. . . and void any chance of Ruger ever servicing the gun for any reason.
:roll:
:roll:
Thanks for all of the great information. While it is good to have options, I will probably not try to convert the .38 SP101 to .357 until the zombie apocalypse has wiped out all of my .38 ammo and all I have left is a pile of .357 ammo.
What I am wondering now is why did Ruger chamber a .357 length cylinder for .38 only? Does it improve the accuracy of the .38 round by shooting it in a .38 length chamber instead of the longer .357? Does it draw somebody like me into buying it because it is somewhat unique (at least to me)? It was the look of that 3" barrel that first drew me in. Whatever the reason, it is a great gun and I will definitely be shooting it a lot.
What I am wondering now is why did Ruger chamber a .357 length cylinder for .38 only? Does it improve the accuracy of the .38 round by shooting it in a .38 length chamber instead of the longer .357? Does it draw somebody like me into buying it because it is somewhat unique (at least to me)? It was the look of that 3" barrel that first drew me in. Whatever the reason, it is a great gun and I will definitely be shooting it a lot.
Besides personal preference, some jurisdictions prohibit magnums for folks like private security or even their own urban police officers. I think over penetration is a concern in a densely populated area.
Just my $0.02 worth.
Terry T
Just my $0.02 worth.
Terry T
Jimbo357mag
Hawkeye
If the gun had to be returned to Ruger for service they would most likely return the gun to stock configuration if they noticed the chance to the cylinder, the same as they would for any work on the gun, including changes to the hammer and trigger or maybe even the forcing cone.Ale-8(1) said:
protoolman
Service-Sixer
They didn't chamber a .357 length chamber for .38. It was designed as a .38 then they experimented with chambering it to .357. That worked out but would only chamber the shorter 125 gr. .357 rounds and were so stamped on the barrel. They then lengthened the frame and cylinder for all .357s. After that they made some .38s for police depts or people who only wanted .38 for whatever reason. They were also chambered in .22 lr, .32 magnum, 9mm, .327 magnum and real recently they added the 4 inch barrel with adjustable sights.
Jimbo357mag said:
Yeah . . . maybe . . . your gun, your call.
Good luck.
:roll:
JStacy
Blackhawk
"If" you could find a 357 cylinder you would probably have to have it fitted and maybe timed to your frame. The accumulated cost would probably be as much as the cost of trading your gun in on a 357 SP101.
I have "customized" a couple of revolver and seldom does the new part , with the exception of action springs" ,just drop in.
I do not know this for a fact but most 357 cylinders are heat treated differently than a 38 cylinder due to the almost double pressure of the operating factory 357 loads. In addition your fixed sight 3" will shoot to a different point of aim with a 357 than it will for a 38 making changing the front sight blade to get it to shoot point of aim. Slippery slope that usually has cost me more money that I had planned .
I have "customized" a couple of revolver and seldom does the new part , with the exception of action springs" ,just drop in.
I do not know this for a fact but most 357 cylinders are heat treated differently than a 38 cylinder due to the almost double pressure of the operating factory 357 loads. In addition your fixed sight 3" will shoot to a different point of aim with a 357 than it will for a 38 making changing the front sight blade to get it to shoot point of aim. Slippery slope that usually has cost me more money that I had planned .
If, someone needs a 357 mag cylinder I know where one can be found. :roll:
That is usually my luck as well, but I guess if I am still asking these kinds of questions, I still have not learned. For now, I will just see what .38 loads will work best in the .38 SP101 and save the .357's for the GP100, which is not likely to ever break and be out of commission anyway.
Speaking of the GP100, I shot a really nice buck with my GP100 during the Kansas rifle deer season, but didn't find it until two days before Valentine's Day. But that is another story...
Speaking of the GP100, I shot a really nice buck with my GP100 during the Kansas rifle deer season, but didn't find it until two days before Valentine's Day. But that is another story...
Update on my SP101 project - I have confirmed that a cylinder chambered in .357 mag does fit and almost function in my SP101 chambered for.38 Special only. I say almost because the trigger does not return properly, it hangs up at the very end of the pull and needs assistance to reset. I am still trying to figure out what is going on,but have been seriously distracted by an unexpected trip to the dark side in the form of a Glock 43. I also notice that the star extractor on the newer .38 is different and not interchangable with the older .357. Does anyone know when that change occurred?
