Just where???

[TinyDee]

Ammo for the big boys. 464, 460 etc. where does one find any easily, reliably and so forth...

 

[devildog66]

454 and 500 can be had through many gun shops, and web outlets such as Buffalo Bore and Double Tap usually carry a good selection. Of course, available and inexpensive are usually exclusive to each other in these calibers... not to mention the selection of rounds is going to limited to the heavier power stuff. You are most going to be needing to invest in reloading equipment.

 

[Vulcan Bob]

As close as your reloading bench! If you have the space and time reloading is the way to go. It will not take many shot's to pay for your eqipment.