The 5-grains-per-pound floor (vertical bow) vs The arrow-length rule: specs compared
Updated 05 September 2026.
8
specs differ
The 5-grains-per-pound floor (vertical bow) and The arrow-length rule differ on 8 specs: the rule, 70 lb example, why, crossbow parallel, draw length, arrow length.
| Spec | The 5-grains-per-pound floor (vertical bow) | The arrow-length rule |
|---|---|---|
| The rule | At least 5 grains of total arrow weight per pound of draw weight | |
| 70 lb example | A 70 lb compound needs a minimum 350 grain arrow including the point | |
| Why | A too-light arrow leaves excess energy in the bow, like a partial dry-fire, and can damage limbs or cams | |
| Crossbow parallel | The same 5-grains-per-pound floor sets the minimum bolt weight on the crossbow side | |
| Draw length | Measured from the nock groove to the front of the bow handle at full draw | |
| Arrow length | Cut about 1 to 2 inches longer than draw length so the broadhead clears the bow shelf | |
| Effect on spine | A longer cut flexes more, so it needs a stiffer spine | |
| Why it matters | Cutting too short risks drawing the broadhead onto the hand; leaving it long weakens dynamic spine |
Questions and answers
How do The 5-grains-per-pound floor (vertical bow) and The arrow-length rule compare?
The 5-grains-per-pound floor (vertical bow) and The arrow-length rule differ on 8 specs: the rule, 70 lb example, why, crossbow parallel, draw length, arrow length.