Nice find Mr. Hallquist as the concern was correct as was the date but different patent number. But it appears that 400 Nitro Express had already informed us on the history of the grip catch:

"The same rotary locking method was then patented by Wilkinson Sword Co. (James Wilkinson) for fastening fore-ends in drop-down barrel action guns. The 1866 screw grip fore-end fastener patent (the familiar side-swinging fore-end lever) was by a Wilkinson workman, which made it Wilkinson's property. Wilkinson Sword Co apparently sold the patent to Rigby before it expired."

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=149435&page=1

I wonder if that mechanic was Charles Harvey?

Are 400 Nitro Express and Kerryman still with us?

Kind Regards,

Raimey
rse