wwb said:http://www.shilen.com/productsRifleBarrels.html
http://www.riflebarrels.com/products/lilja_precision_rifle_barrels.htm
http://www.hartbarrels.com/
http://www.mcgowenbarrel.com/
Now for the question..... Why?
If there's nothing wrong with your present barrel and you only want to change to a different caliber, it's GUARANTEED to be cheaper to sell your rifle and buy a rifle in the new caliber.