I don't think Mr. No Gold ended up as badly as some think. I spoke with Brian LaMaster after the auction/sale and he said he had already sold a number of the items at better prices than the final high bids on-line, and a few sold at much better prices. His on-line sale just seemed to get things started... and his follow-up efforts did much of the real work.
I agree with the comments on lower expectations from an on-line sale. It lacks the excitement of floor bidders being urged on by the auctioneers and the crowd cheering the bidders, and bidders getting nervous and over excited. But I think the big downside in Tom's sale is the large volume of similar, high-quality pieces all being sold at once. When just a few are in a sale, and a couple buyers want one, they have to be more aggressive in bidding and jump in and grab one. With a large number of similar items, all top tier, if he/she misses one, there are always more good ones coming up... so the urgency to bid isn't as strong... and hammer prices often reflect the reduced urgency.
In Tom's collecting field, early fowlers, the number of high-end collectors is less than with Kentucky rifles. I'd think, after a serious buyer purchases one high end item, he is less inclined to chase any of the others as hard. As the sale progresses, with somewhat limited collectors for these guns, I'd think sale enthusiasm would drop... the big lions are satiated, and the small lions don't want to pay the high prices... so prices drop for later items in the sale, even if about as good as earlier items.
Shellby Gallien