All of my 50-65lb Test Pack bare shafts were hitting nock left, even after shortening them and dropping to 125gr points, so I ordered another Test Pack from Surewood for 65-70lb up to 75-80lb spine. I also measured actual draw weight and length and from 20" up to 30" was going up 3lbs per inch according to my spring scale except for 30" to 31" which topped out at 70lbs with a 4lbs increase for that last inch. The resolution on that spring scale is not the greatest, but I am assuming that at 31" draw I'm starting to stack, and that's about what I'm drawing now after trying to correct my form from what it was earlier.
Anyway, at 10 yards every single bare shaft from the new Test Pack is hitting nock left, including an 80lb shaft cut to 31" with a 125 gr point. Most shafts are nock left at up to 20°, and two of the 80lb shafts broke on impact. I did try a 70lb shaft without a point at all just to see, and at least that shaft did hit extreme nock right. I could also get some of the heavier shafts with points to hit straight on if I shot with a short draw of 27-28".
I know everyone says to shoot bare shafts and see where they hit compared to fletched shafts for tuning, but with essentially a new setup I don't have any good fletched shafts to compare to. I'm wanting to shoot at least a 160gr broadhead and was hoping the bareshafts would at least get me into the ballpark as far as proper spine and I could then fletch some and start fine tuning the results from there, but so far I'm seeing no real improvement from 55lb all the way up to 80lb.
I am assuming at this point that, unless my form is so atrocious that I won't get good arrow flight regardless, I have the following options:
Go up even higher in spine even though I'm theoretically over spined on paper at least
Add some thickness to the plate to move it even further from center shot so the bow theoretically "likes" a weaker arrow
Lower my brace height, but I assumed this was more of a "fine tuning" method and not sufficient for how far off I am now
Take some width off of the limbs to drop the draw weight, obviously pretty low on the list of preferred options
I made this bow myself years ago, so if any bowyers can tell me if this is indicative of a defect in design or build, please let me know.
Thanks