Why do people buy odd caliber guns without thinking about finding ammo for them? I would not think about buying a 14, 24 or 32 gauge double without figuring out where I could get shells for it. Do they figure its an easy thing to find on the internet? And if you dont know and dont reload thats double stupid in my book.
here is a market for that rifle, even in that caliber. It always comes down to price. And in this case rare definitely does not make it more valuable to all but an extremely select collector group. As a shooter youd be better off finding someone who is already loading that round or a close cousin.
