These dimensions were taken directly from a Beretta 92 with the factory optics cut and from a Beretta adapter plate.
Because the threaded hole extend into the firing pin channel, a complete strip of the slide is required.
The Beretta slide is hardened to about 40-45 HRC, and it's recommended to use a carbide endmill and carbide drill bit. A carbide spiral point tap is recommended, but using coated HSS with good tapping oil should be sufficient; is using HSS using a new tap for each hole is recommended.
