'Rifle Caliber Brownings Abroad' The brand-new second volume of Dolf Goldsmith's series proves beyond any doubt that the rifle-caliber Browning was simply the most popular and most-used machine gun ever designed. It discusses and illustrates in considerable detail the many variations on the basic recoil-operated Brownings which were manufactured and/or used in over twenty countries, in both World Wars, in Korea and in Vietnam. Of particular interest is the focus on the aircraft Browning, beginning in the Interwar years, in Britain and particularly in Belgium, where to keep pace with the airspeeds of the best new fighter and pursuit aircraft Dieudonne Saive, John Browning's erstwhile chief assistant, twice increased the firing rate of the FN aircraft Browning , first in 1932 to 1,200 rpm and again in 1938 to 1,500 rpm. 367 pp.