Here are some ballistics taken from Remington and some taken from the Lee "Shooter" program:
.280 Remington factory load: 140 gr PSP Core-Lokt, 1 1/2" scope height, 3000fps muzzle velocity. At 300 yds: 2309 fps velocity, with 1657 foot lbs. of energy. Zeroed at 200 yds this bullet was 1.5" above line of sight at 100 yds and 7" below line of sight at 300 yds.
Note the scope height, and the factory bullets ballistic coefficient given as 0.39
.280 Remington handload: 140 gr Nosler Ballistic Tip, 2" scope height, 3000fps muzzle velocity. At 300 yds: 2419 fps velocity with 1820 foot lbs. of energy. Zeroed at 250 yds this bullet was 2.16" above line of sight at 100 yds and 3.25" below line of sight at 300 yds.
Note the scope height, and the Nosler's ballictic coefficient given as 0.485.
The difference of 1/2" scope height, 0.66" higher sight in at 100 yds (to get a 250 yd' zero), and the Nosler ballistic coefficient give us approx' 160 ft/lbs more energy and a 3.75" higher trajectory at 300 yds.
I for one can easily live with the 1/2" higher scope on a thick-breeched Handi, and with the extra .66" sight in at 100 yds. I can easily live with the 10 percent improvement in energy at 300 yds! Even more importantly, I greatly like having a center hold on a deer's lungs being good for a harvest to a distance of approximately 315 yds.....whereas the factory sight in/load was Maybe good for 270 yds.
How much further do you really want to shoot? How much more 'Improving' do you really need?
Take care.