Proper trigger job. Sear hammer engagement is usually the problem, or excessive after travel may cause the weapon to go auto because the sear won't engage the hammer to stop it. The excessive rear travel of the trigger pushes the sear and won't allow it to release forward to the hammer.
If you don't control your shots you will double tap.
This would be a bullseye gun, for carry I set the triggers 3 1/ to 4 lbs.
I looked that up again and you are real close to correct
NRA rules are 3 1/2# minimum and all other center fire is 2 1/2# and it is for safe operation not safety for competition pistols.
carry 3 1/2-4 1/2#
The other source I was thinking about is my Jerry Kuhnhausen service manual it says 4-4 1/2#