Get a used Winchester Model 70...or any standard hunting rifle. If you have a decent hunting rifle sitting in the closet, just use that. A buddy of mine put a PFI scope on his (caliber was 30-06) and had no trouble hitting at 1,000 yards. You certainly do not need a $4,000 precision rifle. The money is better spent on a decent scope with BDC, some Federal Gold Medal Match ammunition and a training course. Only consider a high end rifle when you have the skill to use it properly. Otherwise, you're just spending money to have "the best" with no way to take advantage of its performance.
You don't need a heavy barrel, tactical anything, synthetic stock, or bedding. What you do need is something that will group reasonably well...preferably one inch or less at 100 yards (doesn't mean it will group equivalently at longer distances, but it's a good rule of thumb). A good trigger helps. It does need a scope mount and sling. A bipod is nice, but you can shoot off a backpack instead. Make or buy a sand sock. Then get to work.
Once you train up, shooting steel will be easy at 500 yards. The challenge will be to get the smallest groups possible...but hitting steel will get boring. Then you'll get into reloading precision ammunition, which is another fun hobby.
Most of all...just have fun. Go to the range and find some NRA long range shooters. Ask questions...they'll talk your ear off. Take notes, buy some books, and so forth.