The 400 grain arrow is spined the best, therefore hitting square the best, shooting the straightest, penetrating the most.
You are shooting 125s on all three.
put a 100 even 85 on the 355 and a 150 on the 450 and see if it will bring them into spine.
400 is not a magical number, just with that arrow spine, with the length cut and the 125 used.
Use an arrow that weighs 300 instead of 275 and add a 100 head, still 400 total and see if it shoots as well and penetrates as much.
you are most likely underspined on the 355 and overspined on the 450. Either means the energy in the arrow is not square behind the broadhead, losing penetration.
KE is dictated by poundage/energy. As you show, a difference in 35% of arrow weight only loses 5% of KE, not enough to worry about. The small percentage you gain in momentum from a heavier arrow will only be realized if the spine is correct on all compared weights.
This all relates to tuning issues people have because they buy a bow a set it at 70 lbs or whatever, cut arrows and buy a head weight. Then try to adjust nock and rest. Sometimes it's close and others it isn't because one of the three do not work with the other two for spine. You have three different weights that probably all were charted for your poundage and yet your numbers prove that it's just a start on spine and not an endall.
Spine effects arrow flight more than any other factor.
Kent
