A couple of revolver caliber conversion questions

[Jaymo]

First question, can a 1969-60 S&W 31-1, .32 S&W Long (J frame) be safely converted to .32 H&R Mag by reaming the chambers to accept .32 H&R? Smith made J frame .32 H&Rs, so, I wonder if it would be safe.

Second question, can a 1978 Ruger Speed Six .38 Special be safely converted to .357 Mag, by reaming the chambers to accept .357 Mag ammo?
Is there any difference between the .38 and .357 Six series, besides the chamber depth and caliber markings?

Thanks in advance.

Third question, what is the pressure limit for a .32 caliber S&W J frame?
If I can't safely ream it to take .32 H&R, how hot can I load the S&W Longs?

I'd like to be able to load it for use as a defensive and woodswalking gun.

 

[Driftwood Johnson]

Howdy

Generally speaking, if a gun left the factory chambered for 38 Special it should be left that way. There were very massive S&W revolvers made in the 1930s that were chambered for 38 Special and could be loaded to very high pressures, leading to the present 357 Magnum cartridge. But generally speaking, if the gun left the factory as a 38 Special, it is designed for 38 Special pressures, not 357 Magnum pressures.

 

[BCRider]

So much of this would depend on the metal used in the cylinder and any possible heat treatment of them. Your proper starting point for that would be to ask the makers of these guns this same question. You'd want to include the full serial numbers in the request so they can correctly identify the production year and batch to look for that information.

 

[Jaymo]

Problem is, the manufacturers are going to give the lawyer answer.
I'm pretty sure they'd soil their undies over the Single Six .32 H&R to .327 Federal conversions.

 

[BCRider]

Yeah, there is that.....

If you want to look into this more I'd suggest you start by finding a smith that has the stuff to properly check the Rc hardness of the cylinder metal. And hopefully he has done enough such tests on various .38Spl only and .357Mag cylinders to have a good feel for what is needed to withstand the pressures of the hotter ammo.

It all comes down to the metal properties and wall thickness. The thickness is easy to measure by pretty much anyone. And you're not actually changing it anyway. The metal qualities needs more knowledge and tooling. Yet it's the metal properties issue which is the bigger of the two.

In any event it's still worth writing to the makers. At most it costs you a little time to generate the emails. And they may just come back with something more than the CYA sort of answer.

 

[Jaymo]

I will ask the makers. If I can't convert the Six, and maybe if I can, I may just load it with Buffalo Bore .38s. They're hot enough for most any defensive and outdoor uses I have for it.
Too bad Buffalo Bore doesn't load heavy .32 S&W Long loads. There's a lot more potential in that round than factory ammo offers.
My Lyman Cast Bullet Handbook lists loads for it, using a 115 grain cast lead HP, that runs 1,000-1,100 fps, depending on the powder.
And that's out of a Smith 31.
That's .32 H&R power. Better than most factory .32 H&R power.
Now, if only I can find some HS5 powder, and a Lyman 3118 mold.

 

[CraigC]

I'm fairly certain the Ruger can be rechambered to .357Mag. If a reputable gunsmith will do it, then it is safe. Not sure about the S&W.

The only thing that keeps Ruger from producing a .327Fed Single Six is the necessity for a longer cylinder.

 

[Jaymo]

The cross sectional illustration of the 3118 bullet in the Lyman cast bullet book shows the bullet as a hollowpoint.
Everything I find online about that mold shows it being a flat point bullet.
I realize it's a .32-20 weight. A soft lead SWCHP or Devastator HP would make the .32-20, .32 S&W Long, and .32 H&R into completely different animals.

I'm also thinking about making hard case DEWC bullets, and loading them to the same depth as an SWC, in .32 S&WL, .32 H&R, .38 Spl, and .44 SPL/Mag.
That way, I can load them to the same velocities as SWCs.

Is there any reason that this would be a bad idea?

 

[Jim K]

The .32 S&W Long runs 15k psi; the .32 H&R runs 21k. But that S&W is way over strength for the .32 S&W Long. Many have been converted to .32 H&R and I see no problem in doing so. .327 is another story, though, and I don't recommend chambering that little .32 for the .327 (I am not sure the cylinder is long enough).

 

[Jaymo]

I wouldn't convert it to .327. Pressures are higher than I would be comfortable with.
Even though the 31-1 is a 6 shot, it's chamber walls are thicker than the chamber walls on my 5 shot Taurus 85, .38.

If it was a 31, I wouldn't even consider it. However, since the 31-1 is a J frame, and was designed as a .38 special, it's safe with a lot more pressure than a 31.
Add in the thicker chamber walls and...........................................




ETA, found info about it on the S&W forum. The J frame .32 chamber walls are as thick as K frame .38 chamber walls and 30% thicker than .38 J frame chamber walls.

Then, you have the fact that J frames and other snubs the same size have been chambered in 9mm and .357 Mag, both of which have MUCH higher pressures than .32 H&R.