M. LeF. Curious about which Reilly hammer gun you're talking about. I went through all 300 records I've saved. There only one Reilly which claimed to be "Best quality gun" (SN 24365) There are a number advertised as having "best foliate engraving," But clearly there are a couple of extant guns that have to be "Best guns."
There is a gold-wash gun SN 12532 which may have been made for the 1862 London World's Fair (although nothing in the advert claims it is a "best gun"). (Ted, I know you don't like gold on guns).
There is 16139, a gold washed double featured in DGJ and written about by Douglas Tate (1870) (no claim it is a "best gun.")
And 25161 (1883), given as a prize by the King of Spain, again no claim that it was a "best gun."
There are a few more....but again would be curious about any Reilly "best gun" which turns up.
