GPP stands for Grains Per Pound and describes the ratio between the total arrow weight (in grains) and the bow’s draw weight (in pounds). In other words, it shows how many grains of arrow weight correspond to one pound of draw weight.
Example: A bow with a draw weight of 40 lbs and an arrow weighing 400 grains has a GPP ratio of (400 ÷ 40) = 10 GPP.
Why is GPP important?
- It determines how heavily the bow is loaded
- It influences arrow speed
- It is important for safety (an arrow that is too light puts more stress on the bow)
- It is an important value for both traditional and compound bows
Many manufacturers specify a minimum GPP recommendation in order to limit the maximum stress on the riser and limbs.