do you looking for a 16 ga single shot rifle that is comfortabel to shoot with any load you can get into? here it is: a so called Vogelbüchse a special made target rifle in 16 ga weighting 9,2 kg!
sold by Burgsmüller once this Rifle have a enlarged Mauser 71 action

http://www.egun.de/market/item.php?id=4530729