I use a 6.5-284 and usually stay with the heavies because of my twist, but here are my experiences. The 120 barnes tsx is either spectacular or a total bust. I saw a buck shot 4 times from 150 out to 275 with them, all double lung, before he fell. All were strait thru, "0" expansion. The Hornady 140 sst and amax both were inconsistant in expansion, blow up too close and strait thru too far or if no bone was hit. I think this partially due to the high sectional density inheirent to the .264 cal.
The only bullet I have had consistant results with is the Berger VLD in both 6.5 and 7 mm at any distance. My 6.5 smoked a 128 inch 7 point whitetail at 170 yds, dead right there, bullet fragments exited ,both shoulders broke, internals smoked, meat heavily damaged, no tracking needed. Same results on other deer and on coyotes, coons, and hogs out to about 400 yds. From 500 to 800 they still penetrate about 4-6 in then come apart. I mostly shoot hogs and they usually get up and stagger off with the 6.5 past 500 but they do it bleeding A LOT. The 180 vld in 7mm usually leaves them layin.
Vlds can be finicky to get to group, but their performance is worth it. I think in a .260 the 130 berger would be a killer ticket.