When I lived in Victoria,BC back in the '70s and traveled Vancouver Island for a publisher, I got into every gun shop, sporting goods, pawn shop, hardware store, and anyplace else that might have old ammo boxes. I asked an employee at an old hardware in one of the small up-island towns - I forget which - and he said I was welcome to go down in the basement and check what they had stacked down there.
I found a HUGE stash of VERY old boxes with the original ammo still in them! Both US and Canadian brands. All I was interested in was the 22rf and passed up dozens and dozens of old boxes of big bore stuff. HECK, they may still be there today. I never told anyone about that treasure trove.
I'd bring up an armload of stuff, lay it on the counter, and ask the guy how much. It was ALWAYS cheap!!! I even found a full box of the old forerunner of the 30/06. As I recall it was marked 30/03 or something weird. I bought it for a buddy in the collector club back in Victoria.
Best regards ~ ~ ~ mauser