One thing for sure, however far you know your rifles are sighted in for, thats your max distance without question as you have no business, IMHO, guessing a non fired trajectory.
Elevation is or never should be an issue. Wind can be but with a speed meter and experience, wind at 500 M or 600 yards is a gimme, its so easy for me to drop that first round inside the x ring somewhere with a meter and some known data.....but in the field it can be a bit trickier.
