Mike:
I've examined and greatly lusted after a 28 gauge Zanotti hammer gun at the Vintagers a couple of years ago. Got the seller's contact information, called him later and made an offer, but too late.
It was priced in the $5500 range at the time and appeared to be fairly priced based upon its fit and finish. The gun was beautifully balanced as well and I wish I'd taken advantage of the offer to shoot it, but I was in a hurry that day and passed. I was later told that one of the chambers had the rim cut just a bit too deep and it would only fire reliably with certain brands of shells, although I have no way of confirming the comment or determining if it were just another guy who missed buying it sour grapes. The gun was nice enough, on the outside at least, that I'd have stocked up on the brands that worked and never looked back.
All that being said, I can't really answer your question, but you took me down memory lane on that gun.
Rem