Lyman Series 17AUG .584 High Target Front Sight - 3171080 The perfect companion to your Lyman receiver sight. 17A Target Sights are machined from a solid piece of steel and are designed to be mounted in 3/8" dovetail slots (except 17AEU which has a .360" metric size dovetail). Some fitting may be required. They are supplied with 8 interchangeable inserts (see photo and description) that are locked in place with a threaded cap. Height measured from the bottom of dovetail to center of insert.