Currently, the bore shape in an electromagnetic launcher is usually a rectangle, round, or an inverted arc. A comparison of the current density distribution, induction gradient, moment of inertia, contact pressure, contact state, structure manufacture, and launching precision between the rectangle and inverted arc bore shapes was carried out. We got some results about the effect of bore shape on the electromagnetic launcher. The results show that the inverted arc shape performed better than the rectangle in these areas: current density distribution, induction gradient, moment of inertia, contact state, and the accuracy of armature running. [ABSTRACT FROM PUBLISHER]