Re-barreling a Model 12?

[.455_Hunter]

Any reason why a something like a pinned 12-2 or 12-3 couldn't be re-barrelled with a pinned 10-6 or 10-8 barrel? I understand the pin groove in the barrel threads would need to be fitted once the correct cylinder gap was achieved.

 

[Fishinfool]

I cant comment on thread / pin fit, but I have read barrel swaps on the model 12 (aluminum frame) are risky because of the material involved?

Larry

 

[rincar]

It might crack the frame. I also think that you would need to use a pinned barrel

 

[Inland7-45]

Back when S&W still made the model 12 the had frames available for warranty replacement. The frames were also available to replace frames damaged during the repair process.

I don’t know that the alloy frame is at a high risk for cracking if the correct fixtures are used and the removal and re installation procedure are followed.

I do know that old style frames are no longer available. So if the frame is cracked in the process the gun is a loss.

Unless there is a serious issue with the barrel such as a point of aim or accuracy issue it may be better to leave the gun as is.

 

[Engine49guy]

If I understand you correctly you want to put a Model 10 barrel on a Model 12 frame?

If so then the answer is no.
The Model 12 has a longer cylinder at the front ,
If you install a Model 10 barrel ( and don't crack the frame at the 6 o clock position where it is weakest) you would need to shorten the barrel protrusion length into the cylinder window or the cylinder will strike the forcing cone.

On a strange side note the model 12 cylinder has the same dimensions as the model 19-5 cylinder which is also not recessed.

 

[steelslaver]

I changed the barrel on a model 12 with no problems and used a model 10 barrel to do it, I also replace the cylinder. Both barrel and cylinder were badly pitted

 

[.455_Hunter]

My goal would be a custom Model 12 round-butt fitted with a 3" slab-sided heavy barrel and front nightsight.

 

[Engine49guy]

As Steelslayer said you would need to use a Model 10 cylinder with a Model 10 barrel or have the model 10 forcing cone length,
The Model 12 used a slightly longer cylinder supposedly to prevent bullet jump in lightly crimped ammo (I'm not sure that's fact just what I heard).
The other issue that will arise is that the taper of the frame where it meets the barrel will likely not match cosmetically .

 

[Jim Watson]

My goal would be a custom Model 12 round-butt fitted with a 3" slab-sided heavy barrel and front nightsight.

Years ago, a gun writer showed a M12 that his company connections got him a 3" barrel with full underlug installed. I don't know the source of the barrel. A 581 rethreaded for K frame and cut to length?

 

[Hondo44]

My goal would be a custom Model 12 round-butt fitted with a 3" slab-sided heavy barrel and front nightsight.

Virtually anything can be done. There are always two basic considerations, your skill or whoever is doing the work, and how much you want to spend.

There’s always more than one way to make modifications that range from the easiest way to the best way. Members above have outlined some issues and choices to consider. Now you just have to make your decision based on the two considerations above.

Since you’re using a heavy slab sided barrel, you probably don’t need the extra long Model 12 cylinder to prevent bullet jump. Therefore you could use a model 10 cylinder which minimizes the machining required to fit the barrel. So it comes down to machining cost and time vs. the replacement cylinder cost/availability.

The pinned barrel issue is just a minor machining issue that needs to be dealt with.

 

[StrawHat]

I converted a Model 28-2 from 357 S&W Magnum to 45 ACP. I had the barrel bored and rifled. I fit the new cylinder, frame lug and etc. with time and a file. When the barrel came back, it needed to have one or two additional turns to meet the cylinder. Still did not have a lathe so the shoulder got set back with the same file. Then with the barrel at TDC, I needed to shorten it slightly so the cylinder would close and set the b/c gap. Again, the file.

My point? If you want to do it, you can! It just depends on how ambitious you are or how much money you have.

Go for it!

Kevin

 

[steelslaver]

A guy with a file who knows how to use it can do a lot of very precise work.

 

[steelslaver]

The difference between a pinned barrel and a non pinned barrel is a small shallow notch across the threads in the right location. Not precision at all and easily done with a small file. If you ever set a barrel back a turn or 2 for any reason , like closing the gap or refreshing a burned out forcing cone, you have to modify that notch anyway. The pin in reality does nothing. You can turn a barrel 5 degrees in either direction with the pin installed and cause no damage. In fact if the shoulder is to short and the barrel does not torque up properly and you install the pin you can turn the barrel back and forth that much back and forth with just your fingers.

I made made the new barrel for my 12 from a model 10 heavy barrel. I wanted it short, so I simply turned the shoulder back about an inch, so that the original snub barrel ejector rod would work with under lug on new one, added threads, trimmed off the excess shank, got it to time, adjusted the B/C gap to the model 10 cylinder, machined some flats on the sides of the barrel, then machined a 1/10" groove in the top of the barrel, cut out a ramp type front sight from some thin steel stock and silver soldered it in place. Figured out where groove needed to be for the pin, filed that in. Then tossed the barrel and the cylinder into my blue tank before assembly.

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