Ruger SP101 & GP100 Trigger Spring Kit - Ruger SP101 Trigger Job - M*CARBO

Introduction

This tutorial will guide you through a comprehensive DIY trigger job for the Ruger SP101 and GP100 using the M*CARBO Trigger Spring Kit. The kit includes lighter hammer and trigger return springs, shims for precise fit, and polishing techniques to enhance the revolver's trigger action significantly. By the end of this guide, you'll have a smoother, lighter trigger pull and improved overall performance.

Chapter 1: Firearm Clear

• Before starting, ensure your firearm is completely unloaded.
• Check the cylinder and chamber for any ammunition.
• Always practice safe handling.

Chapter 2: Factory Trigger Pull

• Measure the factory trigger pull weight.
  • Use a scale to confirm the trigger pull weight; it should be around 10 pounds.
• Record this weight for comparison after modifications.

Chapter 3: Parts and Tools Needed

• Gather the following parts and tools:
  • M*CARBO 9.5-pound hammer spring
  • M*CARBO 7.5-pound trigger return spring
  • Hammer and trigger shims (four of each)
  • Synthetic grease with PTFE
  • Tools:
    • 1/16 inch punch
    • 3/32 inch punch
    • Needle nose pliers
    • Flathead screwdriver
    • Dremel rotary tool (optional)
    • Polishing kit (including felt bits)
    • Feeler gauge set

Chapter 4: Removing Grip

• Use a flathead screwdriver to remove the grip panel screws.
• Twist and pull the grip panels off to expose the internal components.
• Remove the disassembly pin and grip retaining pin to detach the grip.

Chapter 5: Mainspring Assembly Orientation

• Pay attention to the orientation of the mainspring assembly as you remove it:
  • The slope of the hammer strut and the two points on the mainspring seat should face the barrel.
• Set the mainspring assembly aside safely.

Chapter 6: Removing Hammer

• Push out the hammer pivot pin with a punch.
• Carefully pull the hammer assembly out, noting its orientation for reassembly.

Chapter 7: Removing Trigger Assembly

• Remove the trigger guard by pushing out the trigger guard latch pin.
• Gently pull the trigger guard out of the frame.

Chapter 8: Trigger Group Disassembly

• Carefully pull back on the trigger to remove the transfer bar and the pawl.
• Note the position of springs and plungers to avoid losing them.

Chapter 9: Polishing Internal Components

• Use a Dremel with felt polishing bits and Flitz polish to smooth:
  • The trigger sear, hammer dog, and internal surfaces where the trigger moves.
• Be cautious not to remove too much material; focus on smoothing rough edges.

Chapter 10: Installing New Springs and Shims

• Apply synthetic grease to the new hammer and trigger return springs.
• Install the new springs while ensuring proper orientation.
• Insert shims to eliminate side-to-side play in the trigger and hammer.

Chapter 11: Reassembly of Trigger Guard and Hammer

• Reassemble the trigger guard, ensuring all springs and plungers are correctly seated.
• Reinsert the hammer assembly, ensuring it aligns with the trigger and frame.

Chapter 12: Final Assembly

• Reattach the grip and grip retaining pin.
• Tighten screws carefully to avoid stripping threads.
• Conduct a function check to ensure everything operates smoothly.

Chapter 13: Testing Trigger Pull

• Measure the new trigger pull weight to confirm the reduction.
• Expect a significant decrease, ideally around 4 pounds compared to the original weight.

Conclusion

You've successfully completed a DIY trigger job on your Ruger SP101 or GP100. This process improves the trigger pull weight and overall function of the revolver. Regular maintenance, including checking the lubrication and cleaning, will help maintain the smooth action you've achieved. Happy shooting!