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.

If they were flying well why did you change the setup?
Not picking just curious?

The 50 grain insert with the 175 gr point made the overall length of the weight longer then just a 225 gr point out front.Might be why they were showing alittle stiffer.Even though they were grouping in the center of your target bare,you might have been on the borderline.I like my bareshafts to show slightly weak and try them with a few arrows fletched up to fine tune them.

QuoteOriginally posted by KodiakMag:
If they were flying well why did you change the setup?
Not picking just curious?

Want to use a lighter fp instead of 225grain. I figured total front weight would have given me the same result. I guess I was wrong.

Weight forward of the end of the shaft has more affect than the same weight behind the end of the shaft.You wouldn't think so but you can test it yourself.Put the 225 point in then find the balance point of the arrow and mark it.Then do the 50 gr insert and mark the balance point again.The weight more forward has more effect on the dynamic spine.

Thanks JimB.