Abstract: A catch device for collecting ejected cartridges and other spent brass from an automatic fire machine gun or the like mounted on a platform includes: (a) a frame portion including an open mouthed, rigid bag frame, and a latch assembly on the bag frame; and (b) a catch bag portion including a collection bag with a hollow interior, a zipper, or a bottom flap with hook and loop strip, closing a bottom slot of the collection bag, at least one attachment mechanism at the top of the collection bag, and at least one flexible cross member extending across the collection bag interior, the catch bag portion being attachable to the frame portion by the attachment mechanism. This simplified abstract is not intended to limit, and should not be interpreted as limiting, the scope of the claims.