Other than what's been previously stated, the best advice I can give for long range shooting (at and animal) is 'get closer'. Most competent shooters can handle a 300 yd shot with a 270 or similar shooting cartridges with a bit of practice. Beyond that, without extensive shooting under varing conditions you are pressing your luck. Holdover is easy once you know your rifle/load - its wind that can cause havoc to an inexperienced shooter.