Would like to see pictures of the rifle as well as the "the breechblock can be rotated through 180 degrees to change the firing pin from rimfire to centrefire" sounds very interesting.

Oh' as to the why ??? As 500 said, there was a time when you could get what you wanted.
I have a old client back in N.J. who owns a best WR bolt in .333 Jeffery (barrel is engraved as such, no a re-bore/re-stamping) and a equally nice Jeffery bolt in .318WR........