Maybe you rifle is not equipped to handle bullets of that calibre JohnnyBravo300 lol This is the first time I have seen a 100 oz silver bullet at auction in Aust, I guess they must be more common over your way?
Good luck trying to find fresh 5.56mm (or compatiable .223) in any quantity. I've had to start sourcing "re-manufactured" (i.e. mechanically reloaded) ammunition just to keep adding to my 5.56mm inventory. Might have to consider stocking 7.62 NATO instead ; tempting to pick up a US-import IWI Tavor-7 just to see what all the fuss is about with bullpup designs.
I like the bull pups, have a kel tech ksg 12g and its compact and alot of fun, holds 15 shells. I bought my first AR during obongos reign and ammo was hard to find then too. Once ammo became available again I filled one of my sheds full so I have plenty stored. It took me a few years of stacking ammo for my different calibers but I got it done box by box. My son has been looking for some 45acp and 38 but not much luck unless you want to pay $2.50 a shot!