A power tool assembly includes an anvil having an accessory receiving end portion that defines a detent bore. A detent is positioned in the detent bore and movable between a retracted position and an extended position in the detent bore. A biasing member is configured to urge the detent toward the extended position. The detent includes an upper detent portion having a trailing abutment surface, a trailing top surface portion, and a leading top surface portion. When the detent is positioned in the extended position, the trailing abutment surface and the trailing top surface portion are located outside of the detent bore, and the leading top surface portion is located within the detent bore. When the detent is positioned in the retracted position, the trailing abutment surface is located within the detent bore, and the leading top surface portion is located within the detent bore.