I checked my ballistic calculator for you.
260gr Accubond 200 yard zero 2850fps muzzle velocity =
300 yards - 2345fps - 3050 FPE = 9" drop
400 yards - 2175fps - 2620 FPE = 20.5" drop
500 yards - 2010fps - 2240 FPE = 41.5" drop
300gr Accubond 200 yard zero 2700fps muzzle velocity =
300 yards - 2345fps - 3160 FPE = 8.5" drop
400 yards - 2100fps - 2700 FPE = 24" drop
500 yards - 2020fps - 2300 FPE = 48" drop
Looks like there is a slight give and take with both bullts.
260gr = slightly flatter trajectory
300gr = slightly higher retained energy
Myself I would go with the flatter trajectory but to each his own...