Hello Sir Isaac and welcome to LRH.
Interesting question and I'll make some assumptions in my answer.
Rifle - Kirby Allen's new Raptor...
The New Raptor is hatching.....
This is a sporter rifle (less than 16 lbs)
Scope - The longest confirmed sniper kill is 2430 m using a NF 5.5-22x50. Depending on what level of resolution you are looking for for targeting you could get higher magnification, but I have the 5.5-22 and can easily focus on small rocks, less than 6 inches, to 1500 yds using the 5.5x setting.
Cartridge - 338 AM. This is the largest 338 cal cartridge that I am aware of and is quite powerful. It's based on the 408 Chey Tac. You could step up to a Chey Tac, Barret or 50 BMG if you were looking for more than a sporter. But Kirby's sporter is no ordinary sporter.
Bullet - The GS SP 295, assuming your shooting is recreational and not live game other than varmints. It has an average BC of about 1 donw to about 2000 fps then falls off to about .76 before going transonic. You should easily be able to get 3500 fps with this bullet out of a 338 AM Raptor which should get you to about 3000 yds of suoersonic flight at sea level.
What ever cartridge yo choose, the GS SP's are very good choice for extreme LR.
GS CUSTOM BULLETS - Specifications for use