This adjustable ring sets the fore-and-aft position of the header auger flighting relative to the feed drum. It is mounted on the auger shaft and secured by a threaded fastener. The ring provides a defined stop for the auger flighting, controlling the gap through which crop material passes into the feeder house. A misadjusted or worn ring allows the flighting to drift, creating an uneven feed that can cause plugging or reduced throughput. The original part matches the shaft diameter and thread specification of the housing so that the auger retains its factory-set clearance without shimming.