For the first decade when 1903 Springfields were customized the standard practice was to use the original Armory barrel and front sight with a Lyman 48 rear sight. The issue front sight is high and if one wanted a lower front sight they had to lower the rear as well. The Lyman 48 sight staff when all the way down and setting on the base goes up and over the hump on the rear of the receiver. I believe that it was Bob Owen who first used a Lyman 48 base for 1903 and staff made for the Mauser which when lowered is flat across. Owen then milled out the rear receiver so the Mauser 48 staff would go lower. When this was done the windage knob was in the way of the magazine cutoff flag. The windage knob was removed and screw slot cut into the shortened screw. Many makers followed suite, some with understanding of why it was done and others not. You will also see the ‘Flags’ on some rifles rounded off as well. There may be many reasons why a custom rifle is found with the windage knob removed but this was the original thinking on the subject.
