Complex sentence: The Browning Superposed was one of the first over and under shotgun designs to be produced, and the last firearm to be designed by John Browning, and after his death the design work was completed by his son Val A. Browning.
Split into simpler sentences: The Browning Superposed was one of the first over and under shotgun designs to be produced, and the last firearm to be designed by John Browning. After Browning's death, the design work was completed by his son Val A. Browning.