I'm in the middle of a .284 build on a Model 7. I have some experience with the .284 and have had no issues feeding the .284 in the standard box of a M7 or a 700 SA.
You can easily reach .270 velocities with a .284 an a box that will let you seat out to 2.85"
Wyatts is another very good option for any 700.

AF
Let your work be shown to your servants, and your glorious power to their children.