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Arrow spine by setup · bolt datasheet

What arrow spine for 30 lb draw at a 26 inch arrow

The starting spine for a 30 lb draw at a 26 inch arrow with a 100 grain point, and the weight floor.

Dry-fire warning

Crossbow bolt data and archery arrow spine, nock and thread data are quoted from each manufacturer's published figures, owner documentation and industry standards, cited on every page. A nock, spine or grain-weight mismatch can cause a dry-fire that damages the bow and can injure the shooter. Confirm against your own owner's manual and the arrow maker's own chart before shooting, and never drop below the stated minimum total weight.

For a 30 lb draw at a 26 inch arrow with a 100 grain point, start with a 600 spine (the 500-600 band), and keep the finished arrow at or above 150 grains total.
This setupmanufacturer data, cited
Draw weight30 lb
Arrow length26 in (cut, nock groove to shaft end)
Point weight100 gr
Recommended spine600 (published band 500-600)
Minimum total weight150 gr, from the 5-grains-per-pound floor
A shaft in this spine

Field notes

A 30 lb youth or light-recurve draw at a short 26 inch arrow flexes the shaft little, so it takes a weak 600 spine. Going stiffer would leave the arrow flying nock-left off the shelf.

Spine is a starting point, not a guarantee, because a 340 from one brand can differ from another. Confirm on your arrow maker's chart at 26 inches and 30 pounds, or bare-shaft test before cutting a dozen.

Whatever spine you land on, keep the finished arrow at or above 150 grains total, the 5-grains-per-pound floor, so the bow is not shooting dangerously light.

The rules behind this pick

Sources: Nock On Archery - Arrow Spine Chart: choosing the correct spine · 3Rivers Archery - How to find the right spine (spine selection charts)