I have an electronic scale for weighing fish. I tied a string to it, reset to 0, then pulled until the trigger breaks. Gives me a real accurate reading of the trigger pull. Being digital, it will let me know such as 3.5 pounds or 4.1 pounds, what ever.

I have another scale/flashlight/turkey carrier/pen holder/tape measure gizmo, for weighing turkey. You hook it over their feet and lift them off the ground and an arrow moves on a weight scale telling you how much your bird weighs. I have used that for the same thing as the electronic fish scale.