You solder a small piece of steel just behind the tumbler notch and file it down to the desired safe sear engagement. Use STAYBRIGHT solder, flows at 430, and apply the heat well back from the notch. If done with care, this will not affect the temper of the notch. If you don't want to solder, you can use J&B WELD to accomplish the same result. This process does the same as the screw that Crocket mentioned, but if you cut too far, you have to build it up again and start over. Also lighten the sear spring by carefully grinding the width of it down some. All production sear springs are way over powered. this alone, can lighten your pull.