.500 spine might not be a bad idea. I use a very similar .400 spine in my compound, so I could probably cop these down and repurpose them if necessary.if you cut shorter they get stiffer, making it worse.......unless you increase front loading to ? 200-250-300 grains.
Bottom line a good thought might be to buy a set of .500 & .600 arrows. you will need them eventually, if you plan to keep shoooting 40 pounds.
a LOT OF FOLKs shoot .500s & .600s up to well higher pounds than 40.
Good luck & keep us posted.
Would anyone be familiar with these? It seems like I could use something like this to further weaken the spine to test the idea. 75gr adapter would let me bump my total end weight up in neat steps without having to buy a bunch of different tip weights.
Thread-In Weight Adapters, 6-pack