450NitroExpress,

I recently bought a Marcel Thys sidelock double in 458wm and priced up the conversion with JJ Perodeau. Worst case cost including reregulation and reblueing if both were required was abot $1700. JJ thought requiring reregulation about a 50/50 chance. If I recall the cost of the rechamber and reconfiguring the ejectors was in the $500-$600 range.

Also the only viable choice, at least on this rifle due to action width and barrel meat is 450NE 3 1/4". 450NE No2 wouldn't work according to JJ.

Hope this helps.

JPK