Carbon arrow spine question

[Shooter#21]

Super Kodiak 45# @ 30" draw. Arrows cut 31.5" long. 145 Gr field tip. Arrows: 500 spine GT with 50 gr aluminum insert and 400 spine GT with standard aluminum inserts. Bare shafted the 400 and it hits close to dead on, except nock high (no big deal). 500 arrow hits nock right but not too bad which is ok since I'm lefty. Seems like a toss up to me. Both arrows seem to hit fairly well and I could be splitting hairs. My release is pretty smooth so I don't think that would cause problems. Which arrow would you go with? Thanks

[nhbuck1]

i would try heavier heads on the 400s and see how they fly but i think the 500s would be better but everyone is different. bare shaft the 400s and see what grain make them hit weak.

[COMPOUNDLESS IN CONCRETE]

The final test for me would be seeing which arrow groups broadheads with field points, if they both do, take your pick.

[Shooter#21]

Good ideas I will try them. Thanks!

[Possum Head]

I would think the 400's with no more weight up front would have been too stiff.Best wishes

[CoachBGriff]

The other way to look at it is that for hunting, it's hard to have an arrow that is too heavy...

But you can definitely have an arrow that is too light.  

I would opt for the .400 and get it flying great just to keep my total arrow weight up.

[damascusdave]

Just for interests sake how did you determine the bow is 45 pounds at 30 inches

DDave

[Shooter#21]

Good point DDave. Actually it is a new bow marked 45# at 28". The other bow was 40 pounds and that's how I came up with the 45# at 30". So the draw weight is closer to 50# in reality. I'm gonna try some weight up front as stated on the 400s and see what happens. Thanks!

[JamesKerr]

Fifty pounds at a thirty inch draw would most likely need a 400 spine shaft with roughly 175 to 200 grains up front.

[Shooter#21]

Update...49/50 pounds at 30" draw...31.5" 400 spine GT carbon with 50 grain aluminum insert and 145 gr point results:

Hits straight at 20 yards and beyond with nock slightly high. With fletching it impacts straight all the way. Groups are tighter. Thanks for the helpful information!