I guess everything has a ceiling price, but at the end of the day, it boils down to scarcity, the motivations of the collector, and how many collectors there are looking for that particular item. For some collectors, quality is everything, for others it may be box ticking, the desire to own something that few others will have, or historical significance, design significance etc.
In the case of Robert Beeman and the Bulldog pistol, he never made me an offer, as he knew I had no interest in selling, so I do not know what his ceiling price would have been. I know he would not have paid anywhere near what he paid for the Haviland & Gunn pistol, as it had no historical American airgun significance, something that was very high on his radar.
The Garanta is probably an example of a rare British air pistol with only a limited number of suitably motivated collectors in the market wanting one. When I acquired mine several years ago, it was only the second one known, and I happily swapped a couple of better quality pistols for it, probably worth £150 altogether. Now that a few Garantas have been in circulation, I suspect that all the collectors keen to own one now have an example and hence the ridiculously (IMO) low price of £60 bundled at Stroud. Either that, or there was a general lack of awareness of its rarity.
The Scout is interesting, as it has a very large ceiling price compared to other pop-outs of similar vintage and quality. I think the Lincoln Jeffries connection must play a part here.
A Scout in about 1926 cost 12 shillings new, equivalent to about £40 in today’s money, taking into account inflation over the past 100 years. If you wanted one now for your collection, even unboxed, it could cost you near £400. (See this interesting thread
http://www.airgunbbs.com/showthread....s-Scout-Pistol)
In contrast a new Webley Mark 1 in 1926 cost 30 shillings, about £100 today. You could now pick up an unboxed, good condition vintage example for about £200. Such is the penalty of having build quality!