How to install the Apex revolver hammer

Today in the Modern Fighting Revolver series, we’re looking at how to install the Apex revolver hammer kit in your S&W K or L frame revolver. This is the most important mechanical upgrade to the modern fighting revolver, as it converts the gun from DA/SA to double action only, and also cleans up the usually terrible factory trigger.

Step 1 in how to install the Apex revolver hammer kit is remove the grips and side-plate. To do this you’ll need a decent screwdriver with an appropriate sized flathead bit, and a small plastic mallet. Once the grips are off, remove the three screws from the sideplate, starting from the back of the revolver and working your way forward. The front screw also retains the cylinder, and looks different than the other two. Once the screws are removed, hold the revolver with the side plate facing down and tap the grip with a plastic mallet. A few good taps and the side plate should pop off. Step 2 in how to install the Apex hammer kit is to remove all the revolver guts. First we take out the mainspring, the long slender spring that runs from the bottom of the gun to the hammer. There’s a screw on the front of the grip frame that tensions the mainspring, just back it out until it releases all spring tension on the mainspring, which you can then remove by hand. Next, pry the rebound slide out of the gun, making sure you don’t launch the rebound slide spring across the room. Then wiggle the hammer up and out. Last, remove the firing pin and spring by pulling their retaining pin at the top of the gun, then sliding the pin and spring out of the channel with tweezers.

Step 3 in how to install the Apex revolver hammer kit is put the new stuff in. We install in reverse order of how we took everything out, so it goes new firing pin and spring, new DAO Apex hammer, then rebound slide/spring. The Apex kit has two springs, one labeled duty and one labeled competition. The Competition Spring in a Performance Center 586 L-Comp gives a 7.7lb trigger pull and still reliabily ignites primers. Installing the rebound slide and spring is the one place you need a specialized tool – the Brownells rebound slide tool. This makes an annoying process easy.

The last step once all the new Apex guts are installed is to close the sideplate up and put the grips back on. Make sure the sideplate is aligned right and the hammer block is where it needs to be, then you can gently tap it with your mallet to seat it. Put the screws in starting with the cylinder retention screw, then make sure they’re snug and you’re done. You’ve successfully installed an Apex hammer and spring kit in your revolver!