Arrow spine for a 40 lb compound at a 28 inch arrow with a 100 grain point: a 600 spine (band 500-600), plus the 200 grain minimum weight. Sourced.
Updated 05 September 2026.
What arrow spine for 40 lb draw at a 28 inch arrow
The starting spine for a 40 lb draw at a 28 inch arrow with a 100 grain point, and the weight floor.
| Draw weight | 40 lb |
|---|---|
| Arrow length | 28 in (cut, nock groove to shaft end) |
| Point weight | 100 gr |
| Recommended spine | 600 (published band 500-600) |
| Minimum total weight | 200 gr, from the 5-grains-per-pound floor |
Easton 5mm Axis carbon arrow shaft (600 spine)
Shop Easton 5mm Axis carbon arrow shaft (600 spine) on AmazonaffiliateFind Easton 5mm Axis carbon arrow shaft (600 spine) on eBayaffiliateField notes
A 40 lb bow at a 28 inch arrow flexes the shaft little, so it takes a weaker 600 spine. This sits in the widely published 500 to 600 band for 25 to 45 pounds.
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 28 inches and 40 pounds, or bare-shaft test before cutting a dozen.
Whatever spine you land on, keep the finished arrow at or above 200 grains total, the 5-grains-per-pound floor, so the bow is not shooting dangerously light.
The rules behind this pick
Questions and answers
What arrow spine for 40 lb draw at a 28 inch arrow?
For a 40 lb draw at a 28 inch arrow with a 100 grain point, start with a 600 spine (the 500-600 band), and keep the finished arrow at or above 200 grains total.