Installing a trigger shim on the left side of this trigger eliminated the trigger drag.

Fortunately, hammer drag is normally easy to spot. In most cases, you’ll see wear streaks on the side of the hammer. Generally, it’ll just be on one side, but if the hammer is moving back and forth on the pivot pin, you can sometimes find wear on both sides. Of course, these wear streaks are easiest to see on a blued or casehardened hammer. If a hammer has been polished bright or is nickel-plated, these marks can be harder to see. Also, drag marks are not necessarily just found on visible portions of the hammer. You can also have drag marks on the lower portion of the hammer that’s covered by the frame. The only way to thoroughly check for drag is to disassemble the handgun.

Smith & Wessons, like many better-quality revolvers, have a small, raised boss around the base of the pivot pin. There’s also a similar boss around the seating hole for the pivot pin on the inside of the sideplate. The function of this boss is to properly position the hammer and keep it from contacting the frame. These bosses can wear over time. I’ve also seen more than one revolver where the owner has inadvertently stoned away or lowered the height of these important bosses in an effort to smooth and slick up the action. No matter how it happens, the results will be the same; the hammer will move side to side on the pivot pin and contact the inside of the frame.

Correcting Hammer Drag
Fortunately, that problem can be corrected easily and quickly thanks to the efforts of one of the finest pistolsmiths in the country, Ron Power. He offers sideplate shims that can be used on any K-, L-, N-, and J-Frame S&W. These shims are made of 302 stainless steel, are only .002 inch thick, and are about .365 inch in diameter. They’re specifically designed to replace worn or damaged hammer-pin bosses and to help position the hammer on the pivot pin in the frame. The end result is less friction and a smoother, lighter action.

The shims are available from gunsmith supply houses such as MidwayUSA and Brownells as well as directly from Power Custom. Use of the shims is simple and straight forward.

First, carefully examine the gun and determine if there is drag on one or both sides of the hammer. Let’s suppose there’s drag on just the left side. Disassemble the revolver and lift out the hammer. Then place one shim over the hammer pivot pin. Reassemble and check for contact on the side of the hammer. If necessary, coat the side of the hammer with machinist layout fluid so that even the slightest contact will show up. Cycle the revolver, and if there is still contact, take the gun apart and add shims until the hammer moves freely.

If there’s contact on the right side of the hammer, you don’t even need to remove the hammer from the gun. Just place a shim over the pin as it projects from the right side of the hammer, replace the sideplate, and check for contact.

One note of caution: Don’t stack up so many shims that they press against the sides of the hammer when the sideplate screws are secured. This could create hammer drag to the point that the hammer won’t even move.