Clocking a S&W revolver barrel

**General Geoff** · April 10th, 2020, 11:02 AM

I've had a 5" model 63-4 (J-frame .22lr) for over 11 years now, and since new it's had a slightly twisted barrel that causes the sights to be slightly crooked. Last night I finally decided to do something about it.

Took the cylinder and yoke out, used some copper jaw inserts, and clamped up the barrel of the gun into a bench vise, clamping on the base of the barrel closest to the frame, nice and tight (but not using a cheater pipe). Then I used a truly massive crescent wrench along with a couple of wood shims for padding, to grip the top and bottom of the frame and twist very slightly.

The crescent wrench I used was large enough to put clamping pressure on both the base of the frame just above the trigger AND the top strap, to spread the torquing forces as evenly as possible and avoid bending or cracking the frame.

Worked like a charm, with the 2 foot crescent wrench it took just a small amount of force to re-clock the barrel to the frame and achieve a front sight 12:00 position. Before it was off by probably 2 or 3 degrees. Frame is fine, no deformation. Now the sights line up very nicely! I'll have to adjust the sights again to get it to shoot at POA again, but one step at a time.

With this particular revolver, I was not worried too much about the barrel-cylinder gap being affected by clocking the barrel because it's on the looser end of tolerances (0.011"). I checked with feeler gauges before and after clocking, it did not seem to have an effect.

**Bang** · April 10th, 2020, 12:56 PM

My Heritage .22 has a cylinder gap of .015" new

I figure oh well, it's only a .22. Just sayin'...wish it was .011".

The usual barrel clamps configuration accommodates the diameter and taper (if any) of most of the length of the barrel, with
resin applied for "tooth". My guess that was not needed because a .22's dynamics is relatively low, and the finish is not blued.

Nice job on protecting the frame from torque damage. Glad it worked out for you

Great photos too!

**General Geoff** · April 10th, 2020, 02:02 PM

Originally Posted by Bang

The usual barrel clamps configuration accommodates the diameter and taper (if any) of most of the length of the barrel, with
resin applied for "tooth". My guess that was not needed because a .22's dynamics is relatively low, and the finish is not blued.

Yeah I thought about fabricating some form fitting barrel clamps and frame blocks, but figured I'd see just how tight the barrel was before bothering. Fortunately it was not tight enough to require special jigs.

**PAwhitetailbowhunter** · April 16th, 2020, 07:57 AM

Awesome work. I had a nice 686 4" that had the same issue. I just sold the gun but would have rather done the work you did to straighten it up. Great post.

**Bang** · April 16th, 2020, 09:45 AM

And the 686 isn't pinned.

**General Geoff** · April 16th, 2020, 10:10 AM

I've been giving some more thought to this, for you guys with larger framed revolvers, I'd use some slightly thicker but soft wood to sandwich the frame into, and then use the vise to squeeze the wood into the frame to form-fit it, then clamp it together as tight as possible with either really big vise-grips or c-clamps on either side of the frame. Then you can do the same procedure with the base of the barrel and the same soft wood, so you can get as much surface area as possible to distribute the load.

Balsa or maybe pine would probably be really good for this.

Another option would be a similar technique but with blocks of thermoplastic, just take a heat gun to them while squeezing so the frame and barrel sink into the material slightly (or alternately, heat the revolver up sans grips in the oven at 250 degrees before clamping up). Easy frame jig!