67-6 question

[BC38]

I was looking at one of these on GunBroker and had a question for the knowledgeable folks around here.

It sure looks to me like it has the same cylinder length as the 66 - just chambers that aren't reamed as deeply.

Could that be correct? Have they simplified manufacturing to use the same cylinder and a barrel with the same forcing cone length - just reaming the cylinders differently and stamping the barrel differently?

Sure looks that way to me....

[Ashlander]

I believe the cylinder on the 67 is a bit less than a tenth of an inch shorter.

[BC38]

Maybe, but to my eye they sure do look the same. If the second photo above didn't have the 357 marking on the barrel I'd challenge anybody to tell me which is which from looking at the two photos I posted.

Does anyone have both a newer model 66 and 67 to measure them both?

[ChiefTJS]

67-5=1.565"
66-8=1.671"

[BC38]

Thanks ChiefTJS
I just looked up the 67-5 and it looks to me like it has a different cylinder than the 67-6 photo posted above. Looks to me like it has a much more obvious gap in front of the cylinder window.


Does anyone have a 67-6 that they could measure? Or does anyone have the details on the engineering change from the -5 to the -6 ?

[LonChaney]

Originally Posted by BC38

Does anyone have a 67-6 that they could measure? Or does anyone have the details on the engineering change from the -5 to the -6 ?

SCSW says the only difference is the 2 piece barrel.

[BC38]

Originally Posted by LonChaney

SCSW says the only difference is the 2 piece barrel.

2 piece barrel? Here is a photo of one (supposedly a 67-6)

Sure doesn't look like a 2 piece barrel to me.

Something is weird here. I wonder if this one has been mis-identified....

[LonChaney]

That or it could be an early -6 that used one of the last of the old style barrels.

[Prodigal Son]

I just measured two in my stable and got similar numbers to ChiefTJS. They are obviously earlier versions than the -6. Use this info at your own risk ;-)

66-1 = 1.674"
67-0 = 1.562"

[LonChaney]

I just looked st the pics again. The first pic in the thread definitely looks like a 2 piece barrel. The pic in post 7 doesn't. Wondering if the pic in post 7 is of a -5.

[Tyrod]

When Ruger first brought out the SP101 in 357mag, it was nothing more than their 38special SP101 with longer reamed chambers. This was the same thing some gunsmiths were already doing. There was a hitch. The 38sp cylinder wasn't long enough to accommodate any 357mag loading over 125 grains. In typical Ruger fashion, this limitation was roll marked right on the barrel. Not long after, Ruger redesigned the SP101 to accommodate a longer cylinder for 158gr loadings. I understand these early factory SP101s in restricted 357mag are kinda rare. Whether they are worth any more, I don't know. They are slightly lighter than later produced 357mag SP101s.

While I don't necessarily condone the action, I wonder if the same thing could be done to any k frame 38sp. I don't know for a fact, but I kinda doubt metallurgically the 38sp+p k frames and cylinders are any different than the 357mag k frames. Just a shorter cylinder. Naturally, most likely, the same projectile weight restrictions would apply. No more than 125gr boolits could be used. I don't know maybe even less. I'll let others do the math.

[k22fan]

Tyrod,

If early .357 SP-101s had a bullet weight limit it probably was to avoid heavier bullets jumping their crimp, sticking out of the front of the cylinder, hitting the frame and obstructing cylinder rotation. Several models of light weight S&W revolvers were marked with bullet weight limits to avoid bullet creep. Regardless of bullet weight .38 Special and .357 Magnum have the same industry standard (SAMMI) maximum over all length, 1.590". That's why many bullet molds have two crimp grooves, one for each length of case. Longer .357 cylinders are for using the .38 Special crimp groove with .357 cases thus creating cartridges that exceed SAMMI length. I find it hard to believe that Ruger ever released revolvers that would not chamber cartridges assembled to SAMMI dimensions.

As for the original question on 64-6 cylinders, it appears BC38 has a good eye for detail. My wild *** guess for why the cylinders were lengthened was to avoid having a conspicuously thin barrel breach prominently on display. So that it does not have to be clocked vertically the portion of the barrel that extends into the frame has the same wall thickness as a one piece barrel's thinnest point under the forcing cone. Model 66-7s were made the same way. I have yet hear of a Model 66-7 or a .357 J frame forcing cone cracking. Perhaps they do not crack because neither has the stress riser that the flat under old one piece K frame forcing cones caused.