Well then, the truth comes out. Good on you. Lets start reasonably. While the .338LM is a tremendous long range performer, no rifle is worth squat without the operator. Get yourself a Remington 700 in .308. That way you can load for both easily, though separately in batches. Components will be easier. Then work yourself out a little at a time. Once it's all muscle memory and instinct, go for the magnum and stretch the limits. Jumping right into a .338LM without setting yourself up right will just make it that much harder for you to get to that LR goal. Walk. Then run.
"Why is is called Common Sense when it seems so few actually possess it?"
Guns only have two enemies: Rust and Politicians.