Taihei Tengoku wrote:.303 is plenty good--so much so that it's not worth retooling to .30-06.
Originally I planned on the Copesidite Army and Marines operating domestic produced Mausers chambered in .30-06, Springfields essentially. Then a major war brews in 1923 and they need to rapidly expand their military overseas. They would buy excess equipment leftover from the Great War to fill their equipment needs. Problem is that their were only about 2,000 decent LMGs produced in the .30-06 during the war. The idea was to re-chamber the Lewis guns into the standard .30-06... only that isn't going to happen anymore.