Jeffery’s Patent Ventometer Long Lee-Enfield Rear Sight Adjuster

This is an original, micrometer adjusting tool graduated from 0 – 150 yds, and has a graduated brass adjustment knob at the top with a flat, nickel steel body.  The slider has positioning stops at both the top and bottom in order to both lift the rear sight riser vertically for elevation in the conventional manner, but also, when flipped over and rotated 90º, to grip the sides of the ladder to allow windage adjustments using the fixed flange mounted on the side of the tool.  The adjuster is in fine, fully functional condition, with clear adjustment graduations and faint, but legible "JEFFERY’S PATENT / No 5304 / W.J. JEFFERY & Co / GUN & RIFLE MAKER / KING ST. ST. JAMES / LONDON markings are present on the face of the adjustment slider.