Over boring is nothing new. I have Bakers and LeFevers which are bored in the .745-.755 range. Newest on them is about 90 plus years old. Often a over bored gun throw very uniform patterns with modern loads. These days they over bore, elongate forcing cones, port the barrels and cryogenic treat the barrels. A lot of technology and hocus pocous go into each gun. Problem is figuring out what is real and what is hype.