The same company made Canuck shells and Imperial shells. I think the factory burnt back in the 70's or 80's. I used to shoot the Canuck shells all the time when I was a kid. They were about the cheapest you could buy that were good. Back home the OTASCO stores carried them. I think OTASCO stood for something like Oklahoma Tire And Supply Company and was a lot like a Western Auto if you remember them.
You have a very nice condition example of a Maxim box. If it is full with 25 of the shells as pictured. It is worth around $20 - $25 dollars retail. Not an easy sell though as it isn't considered the prettiest box. No ducks, dogs, bird graphics etc.. It was a common box from the 70's. Alcan, CIL, Canuck where all great shells to shoot and cheap back then. Maxim was like the max hunting loads brand. I shot a ton of Alcan's and Canuck's in target loads. Even reloaded 1000's till the Win. AA's came out.