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Old January 8, 2020, 02:19 AM   #1
Junior Member
Join Date: January 8, 2020
Posts: 1
Trying to Fix an Under-Regulated Revolver Barrel

Hi Everyone! I've been reading the forum for several years and finally decided to join. For my first post, I'm hoping to find an answer to a rather technical question...

I purchased a S&W Model 60 (J-Frame) revolver and the barrel is under-regulated. When acquiring the sight picture, the front sight is slightly but clearly canted to the right. I test-fired the revolver on a full-sized IPSC silhouette target at 25 yards with my own 158gr .357 Magnum loads and all shots grouped in the top left shoulder area of the target (the target's right shoulder) when aiming for center of mass.

The last time I sent a revolver to Smith & Wesson for service work, it was gone for about three months to have a different length barrel installed, and I had to immediately send it back to them when the work was done for being improperly regulated. Two weeks later it was returned to me better than before but still a hair off. That being said, I would prefer to fix my Model 60 myself if possible.

So here is my question... If the barrel is under-regulated approximately 2° (meaning it needs to be tightened 2° into the frame) and I had the proper vice block for the barrel and a frame wrench with the proper J-Frame inserts (I can fabricate these myself) so that I won't bend the frame, can I simply tighten the barrel myself? Or would I still need to remove the barrel and turn the shoulder down using a lathe?

According to this document from Brownells...:

...S&W J-Frame barrels are threaded 36 TPI and move .028" per full turn of the barrel. I'm calculating that .028"/360°=0.00007"per degree of rotation. So if I need to tighten the barrel by 2°, then that should tighten the barrel's shoulder against the frame by only 0.00014" – 14 ten-thousandths of an inch. That seems infinitesimally small to me, but I'm not sure whether or not such a measurement can be set on a good lathe (I am not a machinist) or would even need to be. Without access to a lathe or the skill to use one, would attempting to simply tighten the barrel myself by 2° – with the proper hand tools – likely crack my frame or over-stress my barrel? Or would this be a safe and reasonable thing to do? Thanks!

Edit: This is not a pinned-barrel model.

Last edited by MM60; January 8, 2020 at 02:21 AM. Reason: adding information
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