Single shot rifles?

Ever see the Lancaster movie, 'Tell them Valdez is coming'?  Sharps again.

Distance shots have lots of variables, and are a juggle of choices.  A lighter projectile, travelling at higher velocity, will exhibit less drop for a greater distance, until wind drag absorbs it's energy, at which time, it will 'fall off' rapidly.  A heavier projectile will hold energy longer, but the larger diameter results in higher wind drag.  Getting proper barrel length, and having a good match of propellant burn pressure and burn time is just as complicated.  Add in spin drift, windage, and rotation of the earth, changes in air density between the station and target, hitting a target at 'long' range becomes quite an exercise.

Tracy's original question refers to 'big bores'... I'm thinkin' you're referring to 'old standard' bores, not the kinds of rounds I'd be using in a 'single shot'... .338 Lmag, .308, or 300Win Mag... or .50...

It's not 'big bore' but we scale down the recoil and enjoy .22 mag from a Savage with Accutrigger and modest glass.  Excellent exercise for long-reach, without needing a long range. 

As for MAKING the long-reach, one can take all measurements, educated estimates, calculate everything, but when it comes to the hammer drop,  having a steady and stable platform, and everything going just-as-planned, there's plenty of providence involved.  Having the opportunity to take a few test-shots, and observe and correct for the results, preferably under same circumstances prior, helps one make that shot.

But that's probably ancillary to the discussion... most of the 'classic big-bore' guys I know, use them with reduced charges for nostalgia events (cowboy action).

I'm not a big-game hunter, if I did, a single-shot might be for the long-range, but I wouldn't be out there without something capable of quick defensive close-ups... big game is, after all, in the wild... one doesn't go hunting, without the environment being equally aware of one's presence.