ok, it is a shot speader (or concentrator, depending on the length of the steel hook). Goes into a cartridge and hooks into the wad
I don't have the book "Early Shotgun Concentrators and Spreaders" by Gary Muckel but did find a quote from it on the internet about the Sporting Shrapnell device:
"The Automatic Shrapnell Co. operated from 36 George Street, Edinburgh, Scotland. It began operations by the inventor, John Watson Johns, with a patent in March 19, 1884. The company may have closed near August 31, 1892 when it seems that Mr. Johns may have died, however, this event has not been substantiated.
John’s patent shrapnell shell is an interesting design with two brass egg shell-like segments filled with shot that are held together by a straight wire spindle fixed at one end to a wad. The segments are meant to slide along the spindle before opening and allowing the shot to spread. Air friction after firing a loaded shell pulls the cardboard and felt wad and attached straight wire spindle through the guide holes in the shot segments and allows the segments to separate and release the shot. The wire was intended to be cut at chosen lengths to adjust the distance at which the shot would spread. Alternatively the wire could be bent or hooked so that the segments could not slide off the wire spindle thus allowing the unit to stay together and act as a slug for use with large game.
Both spherical and conical (or elongated) shaped shells were made. All of the brass segments bare the inscription, Johns’ Patent Sporting Shrapnell No. 5101. The designation No. 5101 refers to the patent number as issued on March 19, 1884 by the British patent office."
