This is the Black Wildebeest taken at a ranged 345m with a 22-250 and a 40gr HV. I realise it is not a long shot in your terms but it points to what can be done.
The bullet entered on the shoulder
went into the thoracic cavity at the second rib
punched through the top of the heart
and exited at the fourth rib.
Nice pass through with good damage where it matters.
I will keep the thinking cap handy and take a serious look at expanding long range bullets towards the end of the year. The current project is to finish up the SP range and do some field work on game with them.