I have a 14 gauge that I bought at auction. It is an external cocking, non-rebounding action.

WILLIAM MOORE & GREY 1865 PATENT 14-BORE ROTARY-UNDERLEVER SEMI-HAMMERLESS SIDELOCK NON-EJECTOR, serial no. 2351, probable conversion from muzzle loader (possibly number 1305), 29in. Damascus barrels, rib engraved 'WILLIAM MOORE & GREY, 43, OLD BOND STr. LONDON.', action incorporating Moore and Grey patent internal strikers with external cocking levers, F.H. Grey patent no. 2743 of 24th October 1865, best border and bold scroll engraving, 13 7/8in. well-figured stock, weight 6lb. 14oz.
Refurbished by Toby Barclay, Heritage Guns, April 2008
The Locks have all the bits you'd expect but lack a way to internally cock the hammers.

Joe