To determine the correct arrow spine for your bow-setup, it is vital to include the point weight in your calculations (the combined weight of the point plus insert/outsert).
If your combination of bow draw-weight and arrow length leads to a spine and point-weight combination that doesn’t suit your requirements,
- arrow too light or too heavy
- FOC too low or too high
You may need to vary your set-up to build the perfect arrow:
- use a slightly shorter or longer arrow
- or use a different point weight
- or reduce your bow draw-weight slightly
- or use lighter or heavier vanes.