All of the front and rear sight blue prints can be found on pages 417 & 418 of Pistol Parabellum Volume I by Gortz & Sturgess

can't get the sight broken loose.
 

I've purchased the Kroil and soaked for several days. I tapped on it once or twice each day or so. I purchased shop tools that are spanner items. They fit in a nut driver tool and allow for some torque by hand. I even tried heat as suggested. I have broken three of those tools and now I think I will abandon the attempt to unlodge stuck screw.
thanks
Jack
:typing:

My advice would be to just keep the muzzle/front sight of the barrel in the Kroil. Once every few days, take the barrel and place it on its side with the screwhead up. Support the underside of thefront sight base with an appropriate sized piece of hardwood. Maple hardwood flooring scraps are good for this purpose since they are very hard but won't likely mar the metal surface. You can likely find them in the dumpster where new homes are being built, or the contractor building the home will probably just give you some.

Then take a flat tipped brass punch or drift and place it on the screw head and wallop it with a small ball peen hammer to jar the threads. THEN try to use the tool with moderate pressure... don't try to "KING KONG" wrestle the screw out. Each time you do this, the Kroil will have a new opportunity to get deeper into the threaded connection between the screw and the sight base. Eventually, this screw will move...

With a properly supported front sight base, and judicious use of the hammer and brass drift, this method should not harm your Luger in any way.

Remember it is not just the screw you are trying to move but the dovetailed sight base.

Jerry Burney