The present invention relates to a device (1; 100) for shooting a casting core (G) that encloses a free inner chamber (I) at its outer boundaries, wherein the device (1; 100) has a mould cavity (5) that forms the casting core (G), which mould cavity encircles an inner slide (2) that extends along a longitudinal axis (LZ) and is bounded on its external side by an outer slide (3) that encircles themould cavity (5), wherein the inner width (W) of the mould cavity (5) is determined by the distance between the inner surface (7) of the outer slide (3) allocated to the mould cavity (5) and the outersurface (6) of the inner slide (2). The device (1; 100) according to the invention enables operationally reliable production, including on a large scale, of casting cores (G) that have a basic tube shape but a fine wall structure. This is achieved in that the inner slider segments (2a-2e) can be adjusted between a receiving position, in which they are positioned closer to each other and to the longitudinal axis (LZ) of the inner slide (2) and the inner width (W) of the mould cavity between the inner slide (2) and the outer slide (3) is enlarged, and a shooting position, which is closer to theouter slide (3) and in which the inner width (W) of the mould cavity (5) corresponds to a specification for the casting core (G) to be shot.