I understand, and have practiced, putting more powder (than typically shown in the reloading books) in cartridges with the TXS bullets as Barnes suggests. And had excellent accuracy out of my 7m-08. But for the 280 I typically use Hodgdons 4831 at 58 grains with a 140 Accubond and Fed 210 primers. I should work up some loads with the TXS for the 280 but am too engrossed with my 308 right now.
Like the boys say, work up them thar loads carefully. You do not want any surprises.
Long