There is a feller on here that has done it before, his name is Fred M. A mighty handy guy, does a lot of good work on these little guns, he has done it before. And to my best knowledge he is the only one that has done his to a .257. A fine caliber and cartridge IMO. Anyways, you wait a lil while and the guys will tell you a little more than i can, and I'm sure Fred would be more than happy to help ya!. Take care and keep your nose to the wind, watch your topknot.
Hank.