I thought very seriously about getting a Schmidt-Rubin K-31, but in the end I didn’t want to stock and reload another cartridge. As you say, that 7.5X55 ammo was pricey.
Probably should have gone for it anyway. By now, I’d have long since recovered from the expenditure.
Freeper Swamp Sniper reloaded for the K-31. Looks like about $1.50 a round these days, but reloading would allow use of common .308 bullets. As usual, primers would be an issue.