There are a number of excellent books available from Collector Grade Publications (www.collectorgrade.com). I have "Backbone of the Wehrmacht - the German K98k Rifle, 1934 to 1945" by Richard Law, and the sequal "Sniper Variations of the German K98k Rifle" On my to get list is "Mauser: Orginal Oberndorf Sporting Rifles", "Mauser Small Bores: Sporting , Target and Training Rifles", "Crown Jewells: The Mauser in Sweden - a Century of Accuracy and Precision", and not unrelated is "The 03 Era".