How To Determine Arrow Length And Weight. Find your bow type and bow weight along with the point weight you plan to use. Choosing the correct arrow spine for your setup depends on your draw length and draw weight.
By joe tapley ( joe@archerycoachesguild.org) increase the point weight on an arrow and the arrow acts in tuning terms “weaker”. The number of inches the arrow deflects or bends due to the weight, is the spine size or measurement of an arrow. To figure out the weight of your arrow, multiply the arrow’s length times the gpi.
Be advised that some archery retailers may be unaware of.
The best method of determining correct archery arrow length requires a bow with a light draw weight and an extra long arrow. The right sized arrow can make or break your shot. For each draw length, record the draw weight on the fingers and the resulting arrow speed. Without the ability to measure joules, there is another way you can determine which draw length is most efficient.