Good quality Camera bag to fit 400mm -500mm Lens

Could someone recommend a good quality heavy duty camera bag to suit I body, a 400mm l- 500mm lens with some extra kit lenses,  and a few essentials could be back pac or sling bag, but needs to be able to handle wilderness type applications, treking and outback adventures here in Australia, heat and dust allways will be constant companians
 cheers

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through the lens behold the glory of creation