Still chasing this rabbit, been reviewing photos of Machine guns, tool rolls, exploded diagrams, sustained fire kits, most small arms pieces, not anything that looks even remotely like this.

On the bright side, I can now probably draw a Vickers gun blueprint from memory.

I have looked over all of the common suspects, the Vickers, Maxim, Bren, Besa, Lewis, Thompson, Lanchester, and including some Germanicon stuff that came up in my search runs.

Next I will probably start looking over recoiless rifles and mortars and their EIS.

It's a puzzle alright.