What caliber does it take to stop one of those??? I bet they would scoff at a wimpy little 375! Maybe a new caliber is order. Maybe a 475 #3 Roo Express. Better make it a triple barrel as well. 24" barrels, so it won't get hung up in the brush. Engraved with a killer roo on the action body. No sling studs, because you will always want to be at the ready when one of those savages step out! A 2" Old English recoil pad to deal with the recoil if you should need to fire all three barrels at once. Talley scope bases recessed into the barrel rib, with an optional 4x14x50mm scope just in case you are not the type that likes to get close, and let the roo decide how he is to die.
A beautiful AAA walnut stock, with an extra Tupperware stock just in case you need to track your roo through a swampy korongo. And lastly, and this is a biggy.....the courage to go in alone with no PH backup. Now THAT may be the toughest order to fill.