I just picked up a 200ET a couple of weeks ago,barrels are marked 18.5 [.729], but I`m not believing it.Its choked bottom .704"
top .696",made in 1993,but shoots like full or xfull with 9 shot.
But it is a purpose built trap gun,so what did I expect?
Anyways,the only reason I can think of Merkel choking them tight outright is to let the enduser open them up to his preference.