I've always assumed the H&H Climax action was a variant of Scott's "Triplex" action. The "Triplex" was used on many gunmakers' guns including my 1886 Reilly 16 bore (shown with Diggory's hand) (there is a Scott patent use number on the gun but otherwise no Scott markings).
![[Linked Image from i.imgur.com]](https://i.imgur.com/VUInQO6.jpg)
Holland and Holland advertised the "Triplex Action" it in the early 1880's:
Holland & Holland 1882 ad for Scott “Triplex Action.” 14 February 1882, “The Sportsman”
![[Linked Image from i.imgur.com]](https://i.imgur.com/5K1w1Sa.png)
Gunman explained what the "Climax"action was all about and how H&H modified. Here is a 16 ga H&H Climax action which to my uneducated eyes sure looks similar to the "Triplex" right down to the crystal cocking Indicator.
https://www.rockislandauction.com/d...d-16-ga-climax-safety-hammerless-shotgun![[Linked Image from i.imgur.com]](https://i.imgur.com/JUvoPkH.png)