DixieFreedomz: I have experience out to 506 yards with my 260 Remington Rifle.
I use the wonderful (and wonderfully accurate!) Nosler 100 grain Ballistic Tips for Antelope, Coyotes and Deer.
I may just be using my 26" heavy barreled Remington 700 VLS in 260 Remington next month, here for Montanas first legal Wolf Hunt in many decades!
I don't think I will be trying for them at anything near 800 yards though - I wouldn't hesitate to shoot at a Wolf at 500 yards though.
I have made several one shot kills on Coyotes and Antelope with this bullet between the 300 and the aforementioned 506 (Leica lasered) yards.
Best of luck with your 260 Remington.
Hold into the wind
VarmintGuy