Carbon Arrows: Shaft, Spine & Component Guide

Carbon arrows are fin-stabilized projectiles made from carbon fiber, launched via a bow. Each arrow consists of a long, straight, stiff carbon arrow shaft, stabilizing fins called fletchings, a pointed arrowhead fixed to the front, and a nock — a slotted fitting at the rear that engages the bowstring. The craftsman who makes arrows is called a fletcher; one who makes arrowheads is an arrowsmith.

Arrow Spine: The Core Specification

Spine is the single most critical technical parameter when choosing carbon arrows for archery. It measures a shaft's resistance to bending: a 29-inch shaft is supported at both ends, a 2-pound weight is hung from the center, and the deflection in thousandths of an inch becomes the spine rating. Common ratings are 300, 400, 500, and 600 — a lower number means a stiffer shaft.

There is an important distinction between static spine (the measurable deflection of an unloaded shaft) and dynamic spine (how the shaft actually bends during the shot, influenced by bow weight, point weight, arrow length, and string material). Point weight has a direct effect: adding 50 grains to a broadhead can require dropping a full spine category — for example, moving from a 340-spine to a 300-spine arrow.

Key Components and Terminology

• Fletching: The arrow fletching stabilizes the shaft in flight by inducing rotation. Vane weight affects dynamic spine and should be factored into arrow setup.
• Nock: The rear fitting that clips onto the bowstring. Nock type and serving weight both influence how an arrow leaves the bow.
• Insert: A metal sleeve glued into the shaft's front end; it accepts screw-in points or broadheads. See our guide to arrow inserts for installation details.
• Front of Center (FOC): The percentage of total arrow weight located in the front half of the shaft. A positive FOC improves stability; excessive FOC can cause vertical dispersion at longer distances.
• GPI (grains per inch): The weight of the bare shaft per inch of length — a key factor when calculating total arrow weight and momentum.

Measuring Arrow Length

Arrow length is measured from the back of the point to the throat of the nock. Draw length and spine rating both influence the correct arrow length for your setup. For carbon arrows used in hunting or target archery, accurate draw length and bow weight measurements — rather than estimates — are essential inputs when consulting a selection chart.

Straightness Tolerance

Premium carbon arrow shafts are graded by straightness tolerance, expressed in thousandths of an inch over the full shaft length. Tighter tolerances improve shot-to-shot consistency, which matters most in competitive target archery at longer distances.