I wasn't aware they could fire the mortar rd with the launcher. That's interesting, two types of ordinance to use.
I was curious of just what was involved in converting the 17 launcher to be able to be used in the 03. So I tried to put my 17 launcher on an 03 and it wouldn't go over the muzzle far enough down to enable the gate to fit past the back of sight base. Apparently the alteration just involved deepening/extending the depth of the inside shoulder a bit to allow the muzzle to go in farther for the gate to close.
Is there a chance you can take a readable photo of the mortar page? Ray