3 gn per inch tubes poor flight

[MD]

Hi just put togeather a few arrows gt 55/75's 3 fletch 5" shield LW, 100 gn brass, 175gn point.  Shooting out of 63# @ 28" longbow.  This set-up works pretty well for me but, I wanted to bring the the total weight up to about 660gn.  I added full length 3gn-inch tubes to get this weight and the arrows fly very nock high and erratic. shooting bare shafts are very scarry in flight. What effects beside weight do the tubes have on spine ect? and how can I get good flight out of this heavy of an arrow?

[USN_Sam1385]

I used the tubes in my 5575's as well, and kept getting erratic flight as well.

I pulled them out, and my arrow is now

GT 5575 cut to 29", 100 grain brass insert, 175 grain point.

Flys great outta my bow, 56# @ 28"

[TOEJAMMER]

Sounds like too much weight up front.

[MD]

I'm not sure about the too much weight up front as the weight up front is the same as before. just added full length weight tubes measured from back of insert to .050" short of nock, so it should be even along the length of the arrow I would assume,