That is the literal version of a pepperbox. I have one that is more roundish- 1859 Allen &Thurber .36

http://www.gunsinternational.com/Allen-Bar-Hammer-pepperbox-31-AH3397-.cfm?gun_id=100374695


I looked at one this weekend in an antique shop in Crescent City... it was only $1400




http://casguns.homestead.com/Sharps_Pepperbox.html
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In the legend of King Arthur, the Fisher King was a renowned angler whose errant ways caused him to be struck dumb in the presence of the sacred chalice. I am no great fisherman, and a steelhead is not the covenant of Christ, but with each of these fish I am rendered speechless.