Have a question on arrow spine. I am getting erratic arrow flight from one of my bows. I had the same problem with this bow before and had put a Bear Weather rest on it and it shot great. Riser was replaced and I am again trying to get it to shoot off the shelf as I don't have another Weather Rest around. Anyway tried from 125 to 200 gr points with no noticeable difference. I built out the side plate and arrow flight improves a lot. ( which helps explain the good flight from the Weather Rest) . Question is is that showing my arrows are too weak? I thought it would make the arrow act weaker , meaning i would need a weaker spine. But reading on the web I'm getting that the opposite is true. Hope that is somewhat clearer than mud. Any insight appreciated.
Yes. Your arrows were too weak to start, though the heavier heads should shoot a little better than the lighter heads because more weight up front softens the dynamic spine. Building out the side plate enables a weaker spine. Or, looked at another way, requires a weaker spine.
Building out the shelf requires the shaft to bend more as it shoots around the shelf.
Just a rough estimate - a 1/16" increase in shelf increases the spine by approximately 5 pounds.
Thanks for the replies, looks like I'm going to be needing some stiffer arrows.