The barrel looks like it will fit nicely, without much stock removal. Only in the Knox form section.
http://i568.photobucket.com/albums/ss122/243myra/P7140004.jpg

After reducing the Knox form diameter, to the same as original barrel, I cut the barrel to length and got it running true, so I can then ream the chamber and screwcut the shank.
<iframe width="420" height="315" src="http://www.youtube.com/embed/QzxMuM3kOqA" frameborder="0" allowfullscreen></iframe>
I managed to get this bore running within a quarter of a thou. You can also see how high the lands are in this Walther barrel. Each division represents .001"

http://i568.photobucket.com/albums/ss122/243myra/P7140005.jpg
The 9.3x62 reamer has a particularly long throat and I took a pic of what the throat looks like, before cutting deeper. The reamer had just started cutting the neck recess.
http://i568.photobucket.com/albums/ss122/243myra/P7140003.jpg

The barrel is chambered, threaded, crowned and fitted to the action, the next thing to do is to cut the extractor recess.
<iframe width="420" height="315" src="http://www.youtube.com/embed/RrSa4jTvYIQ" frameborder="0" allowfullscreen></iframe>
<iframe width="420" height="315" src="http://www.youtube.com/embed/_JTUMWdNM2U" frameborder="0" allowfullscreen></iframe>
http://i568.photobucket.com/albums/ss122/243myra/P7150004.jpg