Was it present at a great battle? Did it have a famous owner? Was it an early example of a piece designed by a famous gunsmith? These are all reasons for excitement.
Sometimes, however, the look of the piece dominates. Is it a particularly elegant or simply unique weapon? With that in mind, here are five of the most 'arresting' examples we've seen:
A gun fit for a Prince
Earlier this year, Universal Live offered a nice example of an elegant weapon: A rare and fine original carbine calibre full-stock officer's flintlock smoothbore pistol with octagon barrel.
The maker, J Probin, is renowned as being the gunmaker for the Prince of Wales. In this example, the walnut stock is fine, with perfect, unworn deep hand-checkering and a sliding hammer safety.
The Golden Indian Colt
In just the second week of 2011, Greg Martin Auctions sold a 'Custom Engraved and Gold-Plated Colt Bisley Single Action Revolver'.
Presented in a mahogany case, the piece bore medium relief Germanic scroll engraved with gold plating and elephant ivory grips.
But most striking of all, the recoil shield at left side of frame depicts an Indian with a war bonnet profile. It sold for a modest $4,818.
Engraved by a master
An auction on New Year's Day, no less featured another firearms which also repaid attention to the details. A 44 calibre A2-1 Colt 1882 open-top revolver featured unpolished nickel and gold gilt and a magnificent raised carved ivory grip.
It was the carving on the barrel itself, however that provoked most excitement, as it was attributed to "the engraver's engraver" Louis D. Nimschke, who was world-renowned for his work on firearms and whose techniques are still used today.
Beautiful, but deadly
At the turn of the 19th to 20th century in the Old West, suspected criminals often died of gunshot wounds before ever being arrested.
One character with a particularly strong 'shoot first…' outlook was Robert D Meldrum, whose work for the Tomboy Mine company proved so effective that they presented him with two truly beautiful shooters.
One of these, a gold-inlaid engraved Colt pistol with a mother of pearl handle, sold at James D Julia for $258,750 in March 2010.
Not to everyone's taste, perhaps, but one of our favourite handguns ever was that owned by Fidel Castro.
A friend of his, engraver John Ek, offered to goldplate his 1958 .34 caliber Colt handgun with spectacular results. The following Bay of Pigs Invasion and Missile Crisis meant that Ek could never return the weapon, which was finally sold at Bonhams in 2005 for a startlingly modest $10,350.
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