"The extruded (blue) magazine "
This type magazine is NOT extruded; it is made from a machined flat blank that is folded and welded up the spine, then machined on the outside. The feed lips are machined into the "inside" of the flat before it is folded, there is no way to form them otherwise.
There are step-wise pictures of the process in a couple different luger books.
One can often see the welded seam if you look inside the magazine, and often there is a slight discoloration in the finish on the outside.
The luger collector community should/would/need to stop promulgating the myth of "extruded" magazines!
Please.
