You could still buy Canuck .25 Stevens Rimfire cartridges back in the Seventies, at the truly outrageous price of $4.75 for a box of 50. This was almost twice what a box of 50 .22 WRFMs cost. Gougers, exploiters, rip-off artists; hissss... How dare they!
However, rifles in the calibers were relatively cheap, at least compared to the same models in centerfire calibers. And of course Stevens Favorites were all over the place. Once in a blue moon you could find one with a decent bore in .25 Rim Fire.
So I would occasionally buy a box of Canuck rounds and bang a few up at the dump for novelty. Once in a while, a box of older stuff no longer made by American ammo companies would turn up at a Gun Show for cheap. And sometimes loose rounds could be had for very little. I remember a plink-fest out at the dump with a Baggie full of US Cartridge Company .25 Rimfire black powder rounds. I used my second best bore Stevens Favorite for this, and was impressed with the accuracy, can-busting power and reliability of the grungy old ammo. Almost all of them fired the first time, and only a couple needed three snaps to get them to go "bang." I'm still impressed.
Now, of course, I'm very stingy with the stuff. Need to go on a squirrel hunt to justify shooting some shells. In the meantime, I can look at the boxes, at least.