Well, scratch the video; I was unexpectedly joined by a friend who was eager to shoot his own stuff. So I didn't get very good video--nothing worth trying to edit and upload to Youtube, anyway. But I have to say that it shot very well indeed. I had backed off of the mainspring strain screw a little and found that I had to tighten it back up to get reliable ignition. They must boresight these or something, because I was able to ring a 10 inch gong with monotonous regularity at 270 yards, once I found the proper elevation adjustment. Windage was spot on, and that "wobbly" rear sight didn't affect things at all. If you saw my posts on my "Iron-framed" Uberti 1860, you'll know that I had to drift my rear sight dramatically to hit something that far, and I wasn't hitting it as regularly, either.
The overbuffing doesn't bother me anymore, now that I know it can shoot. Perversely, the high polish is a detriment in an entirely unexpected way---I spent way too much time cleaning it. On my '66 Uberti, I want the brass to tarnish, But tarnished brass just wouldn't look right against the lustrous blue and gorgeous wood on the HRA. If it is going to be overbuffed, the least I can do is preserve the high polish. So I just had to wax it and buff everything back to a high luster. I must have spent at least an hour cleaning it today. In spite of my misgivings about its over-polish and MIM internals on my Youtube video, it is fast becoming one of my favorite rifles.