Ruger SP101 .38 Spl to .357 Mag Conversion

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AKexpat

New member
I have a Ruger SP101 3" .38 Special, mfg in 1989. I would like to convert the cylinder to chamber 125 gr. .357 Mag rounds. I know this was done by a few pistolsmiths early-on, before Ruger chambered the gun for .357 Mag with the lengthened cylinder and frame.

I have a Clymer .357 Maximum reamer (inherited from my father who used it 30+ years ago to create a .357 Max rifle using a .357 Mag barrel from Numrich Arms that fit a Savage/Springfield Arms single-shot 20ga. shotgun... another story in itself!).

Can I use this reamer to accomplish this by reaming completely through the cylinder holes? The gun has less than 500 rounds of .38 Spl through it and is as tight as when it was new, so I think the cylinder/barrel forcing cone alignment is good enough to not shave lead/copper jacket upon firing.

Thanks in advance for expertise in this matter.
 
Bad idea. Even if the .38 cylinder heat treat and strength are the same as the .357, reaming it with a .357 Maximum reamer would mean that you would have NO throat in the cylinder. The bullet would be jumping directly from the case to the forcing cone, and at a minimum, accuracy would most likely be atrocious.
 
AKexpat said:
I know [that .357Mag conversions were] done by a few pistolsmiths early-on, before Ruger chambered the gun for .357 Mag with the lengthened cylinder and frame.
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This fact does not make such a conversion safe or smart.

Keep in mind that one reason gunmakers use longer cylinders and frames for .357Mag revolvers is to mitigate the possibility that a bullet will jump crimp under recoil, project past the cylinder face, and tie up the gun when the shooter attempts to fire that round. The mere fact that most factory .357Mag rounds will fit in a shorter cylinder does not mean that a longer cylinder is unnecessary.
lee n. field said:
Sell it and buy the same thing in .357?
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For most commonplace and inexpensive guns that are readily available in more than one chambering, IMHO this is generally the only logical and prudent answer. In the vast majority of cases, the cost and effort involved in the conversion far exceeds the difference in trade-in value, and the resale value of the firearm is greatly reduced.

Keep in mind that with this particular conversion, many potential buyers are likely to assume that the firearm is not safe, or turn it down because (a) Ruger is unlikely to be willing to repair it, and/or (b) collector value is nil.
 
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I understand the concerns about heat-treating differences in the different ages of Rugers and pressure differences between .38 Spl+P and .357 ammo. The SP101 is a robust firearm and has always been more substantial than many of the newer firearm offerings (the Ruger LCR comes to mind).

Please explain to me what the difference is between what I am proposing and the single-shot target rifles of the late 19th and early 20th century with a large amount of freebore. I'm thinking Pope.

Just curious...
 
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The gun as an out of production .38 Special is probably more valuable than a new gun. The SP101 is far better suited to .38 than 357. I would roll over the money and then go shopping.
 
@Real Gun:
The gun as an out of production .38 Special is probably more valuable than a new gun. The SP101 is far better suited to .38 than 357. I would roll over the money and then go shopping.
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I appreciate you thinking that it is worth more than a new SP101, with all the new configs that are available. It is not in "collector" condition in my mind. I don't have the money nor the inclination to sell mine and buy new as a retired old fart on a fixed income. I shoot mine with +P ammo when I get some extra cash. Almost as hard as finding .22 LR ammo these days. :eek:
 
IIRC the gunsmith who did those conversions was Rick Devoid.

I'm on the fence. The SP-101 is probably overbuilt as a .38 Special. If the cylinder was rechambered properly (i.e.- the chamber was deepened- *NOT* reamed all the way through) it would probably work. I realize the cylinder of the .38 Special is only long enough for the 110-125 grain .357's.

Is it safe? How was the .38 special cylinder heat treated -vs the .357s cylinder? Was the SP-101 designed for .357 in the first place and all this is a buch of talk? I don't know. Would I do it if I owned the gunsmithing shop?- Maybe not.
 
I don't have the money nor the inclination to sell mine and buy new as a retired old fart on a fixed income. I shoot mine with +P ammo when I get some extra cash. Almost as hard as finding .22 LR ammo these days.
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In that case, I would use it as a heavy duty .38.
 
While Rick Devoid and no doubt others rechambered .38 SPs to .357, apparently with Ruger's approval, running a .357 Maximum reamer clear through the cylinder would ruin the gun. The lack of a cylinder throat would put you back in the era of the .38 Long Colt and without the heel or hollowbase bullets to make it work.

I don't know where you get any comparison between a bored through revolver cylinder and a Pope single shot rifle. His were properly loaded from the muzzle leaving the bullet pre-engraved with and seated in the rifling.
 
IIRC the first SP-101's were marked for 125 grain 357 Mag only; but as noted, there may have been differences in the heat treating for magnum cylinders. I would personally be reluctant to do the conversion.
 
Why?

I own the same SP101, but chambered for .357, while its fun to throw a few .357 rnds through the gun on occasion I personally don't like to shoot very many. The Muzzle rise is rather extreme and honestly it starts to hurt after awhile even with nice Hogue grips. I also have a CCW with that pistol being one of the guns listed. When I carry it I only put .38 spl it, for three reasons:

1) If a follow up shot becomes necessary the time between accurate shots is less, even if it is nice and close, 7ft or less like most self defense shootings.

2) And most important to me....you have less chance of an over penetration situation causing harm to someone other than the intended target.

3) 38 spl rounds are cheaper than .357 magnum rounds, both to buy and to reload.

My advice....enjoy the pistol you currently have in its current configuration, because I guarantee that after shooting .357 rounds out of it you would be back to 38 special anyway.
 
Same advice I always give.

At least 99.9% of the time you are better off selling what you have and buying what you want. The cost of such a conversion will be prohibitive and or the results will not be satisfying.
 
At least 99.9% of the time you are better off selling what you have and buying what you want. The cost of such a conversion will be prohibitive and or the results will not be satisfying.
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And you'll probably end up shooting .38 special in it > 99% of the time anyway.
 
When the SP101 first came out (in .38 Special only), the clamor for more horsepower had gunsmiths reaming chambers for the .357 Magnum cartridge. Problem was you could only shoot 125 grain bullets (due to cylinder length) and if a bullet pulled from a case due to recoil, you had problems. Why not get some hot .38 Special loads from Buffalo Bore or one of the other specialty ammo shops (or reload your own) and call it good?
 
As has been said, why not just use hotter .38s when you feel the need for a more powerful round?
Something on the order of the +P or .38-44 load.
 
At least 99.9% of the time you are better off selling what you have and buying what you want. The cost of such a conversion will be prohibitive and or the results will not be satisfying.
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Hear here! True that...
 
You have a 3" .38 special. You want to use the wrong reamer to bore it out so you can shoot .357 mag?

That seems to me to be on the STUPID side of foolish.

If your world is going to end if unless you can get the performance of a .357 from a 3" revolver, then you get a .357 revolver.

Anything else is foolish, and some things even worse then foolish.

I too am a retired old phart on a fixed income. I'm living on less than half of what I made before. Would probably qualify for food stamps if I bothered to apply, so no pity for a lack of funds.

You could probably find someone to TRADE you a .357 for little or may be no cash. Either way, its not the money stopping you, its the desire. And that's OK, its your gun, do, or don't do what you want with it.

DO take into account that if you ever need to sell the gun, after you have "bored the cylinder through" you aren't going to get squat for it. Altered, the way you propose, its not worth even used market value.

Doing what you propose, (as others have pointed out) #1) wrecks the resale value (possibly of no concern to you..)
#2) could destroy the accuracy of the gun

You'd probably be better off handloading .38s to .357 pressures (ANOTHER BAD IDEA) but the best thing is simply get a .357.

Just my opinion, and worth what you paid for it...
 
Thanks for all of the intelligent, courteous, and not-so courteous replies. I have decided not to go forth with the hypothetical conversion after reading all of the input you folks have given. That's what this forum is all about, eh?

I would have expected a better reply from a staff member, but this post (and other posts) is/are just my opinion, and maybe worth what you paid for it...

To all who are worried about protecting the value of this revolver, there are many out there and my heirs can worry about it when I die.

I have never owned a firearm that was not modified is some manner or another, so we are not talking about safe queens here.

I have added a Hogue Monogrip (because I hate having my pinky hanging in the breeze) and have replaced the factory mainspring (14#) and the factory trigger return spring (10#) to a Wolff spring set (9# and 8#, respectively). Also polished the hammer strut to remove some sharp edges, have shot it with Federal Hydrashok .38 Spl 129 gr +P ammo and it works just fine. Primers are sufficiently indented. The DA trigger pull is now very nice and cocking the hammer is much less an effort, with no hang-up or drag on trigger return. Manually cocking the hammer is much less effort and the SA trigger pull, while a bit lighter, is very nice for target work.

Thanks again, folks!
 
Allow me to make a suggestion. If you were really deadest on converting it to 357 mag, and trusted the safety of such an endeavor, just buy a cheap 30 dollar lee single stage press and a set of dies. You can reload 357 level loads in 38 brass. There is plenty of load data available for such. You could also look up .38-44 loads. It wouldn't be any less safe than what you were contemplating.
 
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