So lets not derail this thread any more than it already is with hk stuff. When I think I am close enough to show a reliable mag option for the hk91 22lr I will post a thread in the hk section. I think we are close but not there yet.
The adapter for all the models has been put on hold. I've tried a bunch of different things but still do not have something that is reliable enough to market. I think there is a reason that the patent was abandoned, its just not a great design. As for the hk mags you know there is this thread about them so I don't know why you post here about them. Follow THIS