How to Install a Double-Set Trigger on a Muzzle Loader

Designed with two triggers mounted in tandem, a double-set trigger converts a muzzle loader firing mechanism into a highly sensitive “hair trigger.” When the rear-set trigger is engaged, the sear (the part of the trigger mechanism that holds the hammer or striker) on the front, or main, trigger is temporarily set to break, or fire, at a lighter pull. After the gun is fired, the front trigger is automatically reset to its standard firing weight. Installing a double-set trigger in a muzzle loader is a simple matter of using a screwdriver to swap the standard trigger for a double-set mechanism.

Things You'll Need

  • Screwdrivers
  • Double-set trigger assembly
  • Trigger pull scale
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Instructions

    • 1

      Confirm that the firearm is unloaded. Check under the hammer for the presence of a primer cap on persuasion firearms; or confirm that the flash-pan is empty on flintlock weapons. Insert the gun's ramrod into the barrel; confirm that the rod reaches into the barrel all the way down to the ramrod's “empty” mark.

    • 2

      Place the gun upside down in a gun vise. Remove the screws from the trigger guard with a properly fitting screwdriver; screws installed in trigger mechanisms are almost universally of flat-head design. Wiggle the trigger mechanism from the firearm with your fingers.

    • 3

      Adjust the pull weight on the double-set trigger. Place the hook of a trigger-pull set scale over the front trigger on the double-set assembly. Hold the trigger assembly in one hand and pull on the scale with the other hand until the trigger breaks. Take the weight reading on the scale. Adjust the longer of the two sear screws on the double set assembly; backing the screw out will lighten the pull weight, whereas turning the screw inward will increase the pull weight. Continue to adjust the sear screw in or out one-half turn at a time, until the front trigger breaks at three and one-half pounds of pull.

    • 4

      Place the firearm in the half-cocked position. Pull the rear trigger to set the mechanism. Back out the small sear adjustment screw, with a screwdriver, until the trigger breaks. Turn the screw back in one full revolution.

    • 5

      Insert the trigger into the firearm and secure the assembly with the screws. Test-fire the unloaded weapon until you are confident that the trigger adjustments are correct.