Revolver barrel threads

[olgeorge]

A question for the mechanical engineers here. Wouldn't the use of a square barrel thread similar to the barrel threads on the US Krag and 1903 Springfield do away with the problem of bore constriction in the threaded area of the barrel on large bore revolvers? Of course, the diameters would have to be closely held to keep the barrel centered. It looks to me like the pressure from tightening would be parallel to the bore rather than having a part directed inward toward the bore. What you think? I know square threads are more trouble to make. I've done a few, not many. The outside threads aren't that hard to chase on a lathe, but tapping the internal ones is more trouble. I have cut internal square threads on a lathe, but in production you'd need a tap set.

 

[Blkhrt13]

Most acme and Stacme threads have wide out clearance on them. They are designed to be a running or use thread. I can't see the slop working out. I'm no engineer. But I do have a drafting degree, 18 years in the machining industry and a whole lot of basic design work experience.

 

[fireman 9731]

I'm not an engineer or expert, but I think the manufactures want some tight threading since the trend in modern manufacturing is to crush-fit the barrel to the frame. Its cheaper and easier than the old way of timing and pinning the barrel. Also, it mostly seems like barrel constriction is just a problem for us lowly lead bullet shooters and a non-issue for jacketed bullets.

 

[38riverrat]

I have thought for some time that the two piece barrels that the new S&W M66 and M69 revolvers have would eliminate the need to over torque the barrels and cause the constrictions. The barrel is indexed with a notch fit at the barrel shroud to frame juncture, and no need to torque for sight alignment.
We shall see.

Best,
Rick

 

[olgeorge]

I wouldn't be surprised if the Dan Wesson revolvers' accuracy reputation was in part due to their barrels not being over tightened. The supplied wrench wouldn't allow for too much torque. The square thread idea was just speculation. The diameters would have to be closely held for centering. Special tooling would be required. Likely not worth the cost.

 

[robhof]

I wouldn't be surprised if the Dan Wesson revolvers' accuracy reputation was in part due to their barrels not being over tightened. The supplied wrench wouldn't allow for too much torque. The square thread idea was just speculation. The diameters would have to be closely held for centering. Special tooling would be required. Likely not worth the cost.

Having owned DW's since the late 60's, I'm pretty sure the shrouded barrel tube is the reason for their accuracy, the barrel tube is threaded at each end and merely hand screwed to the frame and then the muzzle threads are tightened by a nut to the shroud, making for a tension barrel tube and no compression. All the ones I owned and the one I still own are match grade accurate out of the box if properly set up; barrel cylinder gap, consistent torque. Barrel tube rifling was fair to good, but rough on many of my guns, but still dead on.