Chill, I shoot a Sako 75 Finnlight in 6.5x55 and before I started reloading I used 140gn Powershoks, RWS 140gn, and a few 156 gn Norma Oryx, all of which killed deer. I found the Powershoks and the Norma to be superior to the RWS in both accuracy and terminal performance on the deer.
Since starting reloading I have (mainly) used Hornady 129gn SST's, and have been more than happy with them. I find the SST's only need driving at modest speeds to achieve good expansion. I am about to flirt with some Barnes Triple-Shock X Bullets in 130gn, but only because I have been given some to play with. Thank you Neil!
I know the 140gn is supposed to be the best weight in the 6.5 according to the experts, but I could not resist having a play with something a little lighter, I have not succomed to the 120gn BT yet, although I know people who use them very effectively. Their bad press has scared me off. I am going to try the Lapua Mega at some time, but probably in my .308 first.
As said Chill, why do you want to change?
Simon.