Became the guinea pig for the plastic M95 Single Load Devices being sold on the bay.
I'm happy to report it works as advertised.
It is solid and slips right into place like a loaded clip. Rounds placed on the indentation fed smoothly and were picked up by the extractor in a controlled feed as intended.
The latch held the SLED firmly and when the latch is pushed, it flies out with authority, as in don't be looking down at it or it'll poke your eye out on it's way across the room. My rifle was overhauled and put in cosmoline until I got it, some may not have such healthy springs.
I'd imagine the Carcano, GEW 88, and other Mannlicher Clip type rifles might work as well.
Here's photos of the SLED and loading an inert dummy round.