Here is an artists conception of the stamp sometimes found on Lugers and other German firearms that is often mistaken for the U.S. Ordnance Flaming Bomb stamp.
This is an image of an actual US Ordnance "Flaming Bomb" stamp.
Images are courtesy of the late Luger collector, Viggo G. Dereng, a long-time member of this forum, and dear friend to not only me, but many here.
This information is found in the Lugerforum Technical Information which is linked from our homepage:
www.lugerforum.com
This is for the benefit of some of the new members who may not realize we even have a "homepage" as they only know about the discussion pages.