An interesting article by Hendrik
Frühauf???, http://www.freies-wort.de/_/tools/pdfpage.html?arid=698318 , is a pretty interesting find and may more strongly link the Merkels and the Berlin clamshell peddlers with Merkel being the source and probably sourcing Sauer for frames, who in the late 1890s(1893-1899) made a few clamshell double scatterguns with clock-hand indicators:

Forced translation:
"In the 1920s, he had Bernard Merkel was born in 1874 and died in 1954, among other things a lot for
the renowned Berlin firm Barella, and for the resident company in Suhl Franz Kettner, Cologne,
worked. Appeared even more time on the brand Benesu. Which stands for Bernard Merkel, Suhl.
The company had once made a very nice guns, reported early.
Bernard Merkel, Merkel was one of the brothers. Oskar, Karl and Paul Gebhard Merkel have
Gebrüder Merkel founded. Bernhard then worked as Ernst August, the fifth brother,
independently. The end of 1907 have Charles, Paul and Gebhard von Oskar Merkel, separately and in the
Produce Wolfsgrube 14, right next door from Bernhard to start. Oscar worked in the
Judithstraße more than 60 independent gunsmith. He made weapons in excellent quality,
carried out its own developments and had an exclusive clientele, who found in Breitenbach
his research on the history of the various ordnance factories Merkel brothers out. Pity is
He that the house Wolfsgrube 16 and the production buildings have now been demolished. After
Johanna Merkel, she lived a long time in a nursing home Suhler died, was the site
sold."

So using 24 years as the span for attaining the rank of master, Bernard Merkel would have passed that milestone in 1898, which was when things really began to happen for Merkel, etal. Also either the DGJ 2009 Merkel article was based on similar info or supports this info.

The name Benesu equated to Merkel is also interesting as it was thought to be a Berlin firm. I'll check my notes and add info.

Kind Regards,

Raimey
rse