Initially, this was exactly the same as late pre-Woodsman, with the exception of THE WOODSMAN marking on side of receiver. Later there were small changes in sights, trigger and markings. In 1934, barrel profile was again modified to a larger diameter, heavier barrel. This third and final pre-WWII barrel profile lacked the fillet or step-down, as was present on earlier pencil barrel and medium barrel, therefore commonly called the "straight taper" barrel. A significant modification occurred in 1932, when a new heat-treated mainspring housing and stiffer recoil spring were phased in to allow use of increasingly popular high velocity .22 LR ammunition. While this change had widely reported to have taken place at serial number 83790, it was actually phased in over a period of time and a range of serial numbers, spanning at least 81000-86000, within which range both standard and high speed versions can be found. Fortunately, Colt changed the marking on back of mainspring housing (see photo) to allow visual differentiation. Colt also sold a conversion kit to modify older guns for use with high velocity ammunition. Kit consisted of a new style mainspring housing, stiffer recoil spring and coil type magazine spring for use in the very early guns that had a Z type magazine spring.