An endcap assembly for a bat may include a body across an open end of a bat barrel and a core received by the body. In one implementation, the body and the core may be retained relative to one another by a bayonet connector radially spaced from interior sides of the bat barrel by at least 0.3 inch. In one implementation, the body may include a cup having a mouth and receiving the core. In one implementation, the cup is to be radially spaced from interior sides of the bat barrel by at least 0.3 inch. In one implementation, the mouth is axially recessed. In one implementation, the cup and the core are joined by a bayonet connector having a U-shaped slot facing away from a mouth of the cup.