ISO a good long range rifle and scope

1500 yards I’d start no less than a 7mm. Don’t buy into the Creedmoor Fantasia going on. At that distance you’re gonna need dirt signature to see your miss. 

Scope wise, how much you want to spend. At 1500 yards, you’re gonna want good glass because well, you wanna see the target 

@otis-c-white post some samples that you would recommend and I will start the research, thank you sir 

Well in my opinion in no particular order

Nightforce ATACR 5-25

Nightforce NXS 5.5-22

Leupold 5-25

Vortex 4.5-27

technical side you get into first focal plane, second, and fixed

Do the research and then go look through some. You’re looking for clarity, tracking, tactile clicks on elevation and windage.