Well, I finally got a call back from Karl Rohrbaugh this morning.
This was my fourth call from him to date.
He apologized for the delay, and though he offered no explanation for the malfunctions (consistent failures to feed, trouble with slide retraction) of my returned R-9S, he admitted that the gun just "doesn't work for some people", citing the experience of an experienced IPSC-shooter friend who never could get the gun to work, and again offering me a full refund. (I'd sent a copy of my original retail receipt earlier, when he'd called and offered a refund even though he hadn't tested the returned gun at that time).
I accepted the offer, since I must admit I've lost faith in the little gun as a BUG or primary weapon, personally.
I believe the R-9S is a good little pistol, generally quite well made, but suited to a certain limited range of user characteristics. I never could get mine to feed reliably when shooting with a two-handed grip, though it worked much more reliably when shooting it with one hand (?), in spite of the fact that my two-hand grip doesn't involve touching the slide.
In any event, Mr. Rohrbaugh was accomodating and courteous, and I have nothing but respect for him and his products and his manner of doing business.
I'm offering brand new parts and holsters for sale, anyway, in the Classifieds section of the BB.
Best to all here.