how long are your arrows cut? they might be a bit long

Beman and Easton spine rating systems are very easy to understand ... 400 = 0.400" deflection over a 29" span

Honestly I shoot 400 spine arrows out of my 70 pound bow with a a 29" draw ... but they are cut short to about 27&7/8"

the spine charts are ment for a 28" cut arrow typically ... if they are cut longer then you wanna move up a stiffness(say to 340) or if the are shorter move down a stiffness (say 500)

the only spine rate system thats easier to comprehend is CX.. 55-75 = 55 pounds to 75 pounds.

the PSE for instance ... 100 200 300 series .. makes no sense as there is no referance to anything usefull, at least in my eyes anyway