For arrow flight and broadhead flight its usually best to be on the stiffer side for stability and quicker recovery in flight. If your under spined its where you usually run into all kinds of issues tuning and getting broadheads to fly the way you want.
I currently shoot .500 Beman ICS bowhunter arrows cuz they were what my dad gave me, even tho it recommends I shoot .400. Next year I'll probably shoot the CX Maxima reds or blues at .250 most likely cuz that's what the chart recommends at 27.5" draw length and 50 pounds. I'm just following the chart recommended for the arrow based on draw length and weight Sent from my iPhone using Bowhunting.com Forums
I shoot a Matthews Z7x @ 27.5"/62lbs and have actually found that my arrows fly truer with the next stiffer spine than what is recommended by the arrow mfr's charts (Beeman & Carbon Express)... I basically had a really hard time tuning my bow and started thinking it was a spine issue so I bought some stiffer arrows and all my problems went away!
I shoot a halon 32 at 70 lbs and 29 inch draw I'm shooting Easton full metal jackets 320s the new 6mm size at around 425 grains and they fly true and great I have no issues tuning them or anything I have them cut at 28 and 3 quarters of an inch so they sit right in line with the front of my riser.
