Winchester Repeating Arms Xpert, Bolt Action Rifle, 21 SHARP, 18 Barrel, Adjustable Rear Sight, Polymer Stock, 10 Rounds 5252001003 The Xpert from Winchester Repeating Arms combines accuracy, dependability, and style in a lightweight bolt-action package. The Xpert features a precision Rimfire M.O.A. Trigger, button-rifled barrel with Bentz-style chamber, and lightweight polymer stock.