I decided to shoot GT 500 spine since I was at the border line of being weak spine with the GT 600 spine. One thing that I'm confused about is adding weighted inserts. I was able to get my GT 500 spine arrows to fly well w/ 225 gr fp bareshaft. They were grouping center of my target. So I decide to add a 50gr brass insert and drop down to a 175gr fp so forward weight should equal 225gr total. When I shot the arrows it hit left of the target showing stiff. When I put back the 225gr fp w/ 50gr insert the arrows hit center again. My question is, does adding a brass insert stiffens the front portion of the shaft? I thought add more weight will weaken it but this shows otherwise. Am I doing something wrong?
42lb draw weight
28 1/4" DL
Right hand shooter
Hoyt Excel w/ SF Carbon Long Limbs.