Put a lot of money into the optics. Something on the order of the price of the rifle - even exceeding it - is reasonable. I took a precision long-distance rifle course, and put a $500 Leupold scope on a $2000 rifle (Steyr Scout); if I go back, it will likely be with a $1000 Leupold (higher tactical model) on a $1000 rifle (Remington 700)
(prices are very approximate).
Most "good" rifles can do 1MOA accuracy or better - that's just 10" at 1000 yards, good enough for most social applications. Sure you can get sub-MOA performance for more money, but can/will
you be able to shoot that well?
At long range, optics become crucial.
1. The clarity and uniformity of the glass must be precise enough to
see the target clearly; a crisp image at lower magnification is preferable to higher magnification of a murky image. Person-sized targets get very small beyond 600 yds. Even high-contrast well-defined targets are hard to pick out as you approach 1000 yds; you'll be straining the limits of your eyes, so you don't want the optics muddling the image.
2. Elevation/windage adjustments must be comparably precise; unlike most applications where they are set once and left alone most of the time, sniping requires frequent adjustments which had darned well better be accurate and consistent.
2.5 The adjustment knobs should run thru the full range with one turn, typically with each click making a 1MOA adjustment. 1/4MOA adjustments sound appealing, but few things suck more than finding out the hard way that you're a full turn off, then wasting time trying to figure out which way you have to crank that knob.
3. Reticle choice is significant. "Mildot" reticles usually cost more, but are worth the cost in providing a convenient means to measuring the target for distance estimation - so long as the dots are etched precisely enough.
4. Holding all this together should be rock-solid rings and base. The base should have a 20MOA slope, vital to giving elevation adjustments range from 100yds to >1000yds; no base slope can limit a 1"-tube scope to 600yds. This I found out at a bad time, and had to resort to cheap ($45) rings which had shims providing the needed 20MOA slope ... which apparently shifted (!!!) before making a crucial 100yd shot at a 1" target. Paying over $300 for rings & base is reasonable.
Remember: if that crosshair is not spot-on at your range of operation, you'll miss. If the end of the scope unexpectedly moves 0.001" off center, you'll be off by 10" at 1000yds. If the optics are not crystal clear, you might not even see the uncooperative target at that range.
Your choice is either pump money into the optics so you can hit with the first shot, or pump the money into a fast-cycling action so you can try again quickly. Don't get me wrong: autoloaders are certainly useful and can be just as accurate as a bolt-action ... but with sniping, the goal is to not need a second shot. Put the money in optics.
How do you know how much to put into what? Just make sure the tools are better than the user ... and that the user strains the limits of the tools.
I will say that I have never been part of a the military, and anything I know about sniper rifles and sniping and precision shooting, I have been taught by the fine gentlemen at
Storm Mountain. They prefer the Remington 700.