Quick Answer
To test arrow spine before a big hunt, draw the arrow back to your anchor point and hold it for 10-15 seconds to check for oscillation, then measure the arrow's weight and length to calculate its spine rating. You can also perform a simple test by shooting the arrow into a bale of straw or a sandbag to observe its flight pattern. This will help you determine if the arrow is too stiff or too flexible for your bow.
Determining Arrow Spine Rating
To determine the arrow’s spine rating, you’ll need to know its weight and length. A common method is to use the weight and length formulas: Spine (in inches) = (Weight in grains x 28.8) / Length in inches. For example, an arrow weighing 600 grains and 28 inches long would have a spine rating of 72 inches. The lower the spine rating, the more flexible the arrow.
Testing Arrow Flight Pattern
To test the arrow’s flight pattern, shoot it into a bale of straw or a sandbag. Observe how the arrow behaves: does it oscillate or vibrate excessively? Does it fly true or wobble in flight? If the arrow is too stiff, it may fly too consistently, while a too-flexible arrow may wobble. A well-balanced arrow should fly smoothly and steadily.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.