When I use Stu's calculator my dynamic arrow number is 69.9, my bow number is a 70.0 but my arrow GPP is only 8.4. I've always been told use an arrow weight of at least 9 gpi which my set up does but the dynamic numbers are way off ( over 15). What am I missing.
Use a stiffer shaft and add more weight up front or cut the shaft you have shorter if possible and add more weight up front.
How much does your arrow weigh now?
I am with Randy. Getting under the 9 gpp can shorten the lifespan of your bow. I like 10 gpp for my bow.