I switched to a release trigger several years ago. Since then my trap scores have improved. It seems to me that lop with a release should be measured from the set position rather than the released . If this is true then the stock would need to longer by the amount of the set travel.
That increase in LOP with a release trigger sounds great in theory, but in the real world I’m not sure it matters. True LOP is (or should be) measured from the center of the pistol grip to the butt, not from the trigger to the butt. Yes, I know that all the stock makers measure trigger to butt, but the trigger finger is so flexible that moving the finger 1/2″ one way or the other really doesn’t affect LOP. It’s when you move that hand holding the pistol grip that LOP comes into play.
Try this: Mount your gun with your hand on the pistol grip normally and “sense” the length of pull. Now move your pistol grip hand as far up the pistol grip as you can. Mount the gun. I’ll bet the LOP feels longer. Now move your hand down the pistol grip as far as you can. Mount the gun and I’ll bet the stock feels shorter.
Stock length hasn’t changed, but the position of your gripping hand has and that alters LOP fit.
Moving the trigger finger in our out a bit doesn’t have the same effect.
Shotgun Report’s Technoid