Did I cause a misunderstanding in my previous post? Regarding the image of the numbered armour plate with dimple and straightening hammer tool mark impressions: I am quite confident this dimple tool mark impression was made following the heat treating process, and that it was done by a method similar to the Brinell or Rockwell testing protocol. This same plate has these test marks at regularly spaced intervals. It has nothing to do with a rifle cartridge bullet being fired from a barreled weapon or other device for testing purposes.
As Hanno indicated:
"The Brinell hardness test was one of the most widely used hardness tests during World War II . For measuring armour plate hardness the test is usually conducted by pressing a tungsten carbide sphere 10mm in diameter into the test surface for 10 seconds with a load of 3,000kg, then measuring the diameter of the resulting depression" (paraphrased)
Reference: CALCE and the University of Maryland, sourced 25 May 2013 from WWW at URL:
http://www.calce.umd.edu/TSFA/Hardness_ad_.htm, quoting from
http://www.wargamer.org/GvA/background/hardness1.html (does not load)
Posted in response to:
"If you look at the test dimple on the first pic you can make out a small "punch" mark in the middle. That dimple doesn't look like a .303 test hit, too even! On a "hit" you would have some distortion around the outer edge as all rounds don't break up the same on impact."
and:
"The dimple in Michael's picture is nothing like a bullet strike, either AP or Ball. The edges are too defined."