Welcome to the forum and to reloading. Lots of experience here.
I use Magnum primers in my 280AI.
IMR7828SSC gave me stellar performance with the 168 ABLR.
Remember the start low and work up
JD338
Ben,
I started out using a Leupold VX-3 2.5-8x36mm and shot a bull elk at 350 yards. I shot it out to 500 yards with no problem. It now has a VX-6HD 3-18x50mm and it's more than enough scope for my hunting and shooting needs. Your scope options are good ones, just depends on what you are going...
My favorite long range rig...
Remington M700 blueprinted action, heavy duty recoil lug, Krieger 27" fluted #5, Williams Tactical brake chambered in 338 RUM, HS Precision Hunter stock, Leupold VX-6HD 3-18x50mm scope in PRW rings and picatinny rail.
2" groups at 800 yards.
JD338