Anyone have TAP that can run some numbers for me?

[Gamblin Guy]

Looking to check some numbers on Easton Axis 340's cut to 28 inches, thinking of using the brass inserts to gain some FOC but want to make sure I don't go too much...

[D-Rock425]

What grain tips?

[Gamblin Guy]

D-Rock,

Wanting to try the NockTurnal Helios, they are 54 grains so thinking the 75 grain brass inserts with 100 grain heads would offset the weight in the back, it calculates out to about 11% FOC, just worried about the spine on the 340's.  Total arrow weight is about 505.

Bow is a 2010 PSE Vendetta XS, 29inches and 68 pounds.

Thanks.