I echo what Greybeard said. I have one of those on my 243, been there for a year now and had some use. They really are a great scope, extremely clear and very bright as well. I got it for the versatility of 2.5-16 zoom. That would be the perfect scope for a 257 WBY. I have the Bushnell 4200 3/9*40 on my 257 and I know it would be a lot better with the 6500. When funds allow I will change it out, the 4200 is a fantastic scope too but lacks the extreme magnification change of the 6500. The 257 Roy would be a perfect fit.
PS, don't know how you feel about Ebay but I ams elling some guitars there now, I checked on the 6500, $520 delievered, a bargain!