Abstract: The invention relates to an upper receiver for a firearm, comprising a supporting part, which supports a barrel bushing for receiving a barrel, a guide for a longitudinally movable breech carrier, and an anchor for a sight. The guide for the breech carrier is formed on the underside of a rail block preferably made of metal which has the anchor for the sight on its upper side, and the supporting part is also preferably made of metal and mounted both to the barrel bushing and to the rail block via removable fasteners.

Abstract: The invention relates to an upper receiver for a firearm, comprising a supporting part, which supports a barrel bushing for receiving a barrel, a guide for a longitudinally movable breech carrier, and an anchor for a sight. The guide for the breech carrier is formed on the underside of a rail block preferably made of metal which has the anchor for the sight on its upper side, and the supporting part is also preferably made of metal and mounted both to the barrel bushing and to the rail block via removable fasteners.

Abstract: The present disclosed subject matter relates to a housing for a firearm with an exchangeable barrel, comprising a bushing into which the barrel root of the exchangeable barrel may be inserted in the axial direction. The bushing has a slot in the axial direction and a clamping device for bringing the slot from a starting position into a narrowed position. The bushing is configured to receive the barrel root in a press-fitting manner when the slot is in the starting position and has a spreading device for bringing the slot from the starting position into an expanded position.

Abstract: The present disclosed subject matter relates to a housing for a firearm with an exchangeable barrel, comprising a bushing into which the barrel root of the exchangeable barrel may be inserted in the axial direction. The bushing has a slot in the axial direction and a clamping device for bringing the slot from a starting position into a narrowed position. The bushing is configured to receive the barrel root in a press-fitting manner when the slot is in the starting position and has a spreading device for bringing the slot from the starting position into an expanded position.