The linkage in the Mallory, "Krag Rifle Story", photo (that 'Local Boy' matched up with the OP's receiver) I believe is an error. It has nothing to do with Firing the mechanism.

The Linkage seems to be the type that was used on Krag and 1903 Springfield rifles adapted for use on U.S. produced "Cummings Sub-Target Gun (or rifle) Machines".

IMHO - It is not a part of the artillery sub-caliber devices. I think the pairing with the 'not quite finished/no serial number' Krag action is a mistake. Sub-Target Gun Machines and Sub-Caliber Devices are different animals. Someone combined parts of unrelated devices.

The "Sub-Target Gun Machine" was a 'rifle shooting simulator'-'training aid' that saw use in the U.S. and British Army & Navy, Military academies, military and public schools, from the early 1900s to around 1920.

It worked on the principle of the pantograph. A rifle attached to the Cumming's machine was aimed at a distant target. A needle mechanism moved in alignment with the rifle's bore, poised to strike a miniature target that was aligned with the distant target.

When the rifle was 'dry fired', a linkage was moved by the rifle's Cocking-Piece. This action pulled a cable that caused the needle to move forward and pierce the miniature target ("sub-target").

If everything was properly adjusted and aligned, the pin hole on the miniature target would correspond to the sight picture through the rifle sights, when the trigger was squeezed. (Yes, we all want one for our Game Room)!

Attached: Said Linkage on a Krag, Linkage on 1903 Springfield, Post Card that is also a miniature target with pin holes.

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