u can find supergrade swivels on ebay some real some i'm not sue about. in the states thats a 4 to 5000$ rifle theres a nice 257 roberts prewar i think on griffin and howes used gun section for around 4k and they are not super rare like a 7x57. thats a nice rifle.i have 2 270 prewar carbine a 48 transition a fifties 300 h&h ruined by reamer to 300 weatherby and a 51 rebarreled to 375 h&h. they turn into an obsession . the cool part is they only made one length action basically a magnum length and just added machining steps to make a magnum. i've seen them in 404 but have heard of them in 416 and 458 lott.