My first trip to the range with my new Smith & Wesson Model 640 went from eager anticipation to sheer disappointment. The first five shots downrange at 10 yards went into an acceptable cluster on the right edge of the target. I shot another five shots at the same target shooting with my support hand pulling the trigger and my strong hand steadying the gun in a good two-hand grip to make sure that I was not inadvertently jerking the trigger. I shot another five-shot group on top of the first group. Then, it dawned on me to look at the sights on the gun to see if they were centered. To my surprise and embarrassment, I then recognized that the front sight was not centered on the barrel. In fact, part of the sight base was not fully in the dovetail cut for the sight.
I tried tapping the sight with a small brass hammer to move it to center but it would not budge.
How would you suggest I go about getting the sights properly seated to get my shots closer to the center of the target?
T.B., Augusta, GA
My first recommendation is to send the gun back to the manufacturer to get the sights centered as well as to have the gun test fired for point-of-aim, point-of-impact. It goes without saying that sometimes a manufacturer—all manufacturers—let something out the door that, for a variety of reasons, is not 100-percent perfect. Nevertheless, how the manufacturer handles those mistakes is what represents the quality and integrity of the company overall. I am sure that contacting its customer-service department will result in an apology and a call tag for shipping the gun back to the factory to correct the deficiency.
If you decide to correct the problem yourself, you will need a padded-jaw vice to securely hold the barrel so it will not turn when applying pressure to the front sight to get it properly positioned.
Before trying to move the sight, inspect the dovetail and the sight base closely to make sure the sight base is aligned with the dovetail. Look for any burrs or irregularities where the sight and the dovetail are joined. These occur when the sight base and the dovetail are not accurately sized for one another, and they are force-fit by mechanical sight pushers at the factory. If these conditions are observed, I again recommend a return trip to the factory for your revolver.
If there is no observable damage on the sight or the dovetail, there are two possibilities that depend on what side of the dovetail the sight was started into originally. For example, the sight might have been pushed too far through the dovetail, leaving the forward edge exposed on the opposite side of the insertion point. Or the sight may have been started into the dovetail and not pushed far enough to get it centered. If you have a sight pusher available, that method of adjustment would be the best option for moving the sight to center of the dovetail.
If a sight pusher is not available, a suitable hammer and punch are the next best option. The punch should be made of a material softer than the sight or the barrel’s steel so as not to damage either when moving the sight. A bronze or brass punch with a flat end the width of the dovetail should work for you.
You will need a bigger hammer to move the sight rather than the small brass one previously used, especially if the sight is tight in the dovetail. I’d recommend a 1- or a 1.5-pound dead-blow hammer to generate the necessary force to move the sight, but absent the bounce of a standard hammer.
If the sight is resistant to moving back to the center of the dovetail by applying pressure to the sight base (it is not a good idea to apply pressure to the sight blade itself because the blade may break off and leave the base in its original location), position the punch against the sight base in the dovetail and drive the sight out the side from which it is protruding.
Inspect the sight and the dovetail for burrs and/or irregularities in the flat engaging surfaces. If rough spots are encountered, fix them by dressing them lightly back to their original shape with the help of a Swiss needle file of the correct contour. The rule here, when using files on sights and dovetails, is to do the work on the least-expensive part. That should be obvious.
Once any irregularities are cleaned up, the sight should start into the dovetail by hand with the bearing surfaces in alignment. Prior to starting the sight into the dovetail, lightly lubricate the bearing surfaces so as to ease the push with the hammer and finish with the punch.
In the rare event that the sight is still resistant to moving into and across the dovetail, a few passes of the bottom of the sight base across an abrasive to remove a slight amount of material will allow the sight to move properly in place and still be sufficiently tight to maintain its position over time.
This is an exercise of patience—not force. Taking your time and using the proper tools will yield the results you are looking for. The time, effort (and a tad of patience) will have you back in the center of the target with the sights in the proper location.
