I have two 280's, one a fifty+ yr old Rem. Model 721 w/24" factory barrel, the other a 15 yr. old Rem. Mod. 700 Mountain Rifle. The 721 will shoot bug holes - best group ever was .294 five shot group at 100 yds, with 53.6 gr. IMR 4831 and reloaded Rem cases, Sierra 160 gr. SBT's, CCI LR primer, seated 0.015 off the lands. Anything higher and primer pockets start to open up, and other pressure signs.
The Mountain Rifle, because it has the slim profile barrel, doesn't like anything heavier than 150 gr. bullets. Best results with it has been .355 at 100 yds with Nosler 140 gr Partitions of all things. All else opens up to about .500 at 100 yds. It did take a 320+ bull elk at 360 yds, one shot kill, bull ran uphill about 300 yds, and fell 600 yds down into a valley. Bullet was Nosler 160 gr Partition, loaded with the 53.6 gr of 4831, shot was quartering away, 25 yds lower in elevation. Bullet entered over left hip, destroyed lungs and heart, and lodged behind the right front shoulder. Retained weight 85%.
Wouldn't trade either for anything in anybody's safe.
Watch your pressure signs closely, especially if you use Rem or Fed brass. Haven't tried others, leaving well enough alone.
Good luck and enjoy.