Been thinking about a cull hunt in OZ and using a 45-70 or 450 Marlin. With the travel limits of ammo and the number of rounds used on a cull hunt, can a local gent give an idea of availability and price for either or both of these?

I shoot a 45/70 and although I reload I have sometimes had to buy factory ammo. Most of the larger stores will carry a few boxes no problems.
It's between $40-$60AU a box depending on what you get.

The 450 Marlin is a different story though, it hasn't been that popular here and there are not many (if any) stores that will carry it on the shelf and would probably have to order it in for you.
That's not to say that it's not available at all, but you'll just have much better luck finding 45/70.

For starters we dont have the variety of factory ammo available that you have in the US. In the case of the 45/70 its normally the stuff designed for Trapdoor pressure levels, so if you are after something specific you might have to re-think what you do.

Whoever you book through should be able to arrange factory ammo for you and advise whether someone local can load some ammo for you. Components are readily available in most major capital cities.

Joe