look up a few posts to Kaywoodie.... far left, that thing looks HEAVY!
I fabbed one yesterday out of 3/8 dowel and a hardwood furniture button, still waiting for the spring from Numrich.
Solid steel stock! May be one of the earlier mentioned heavy plugs. I did take it out of an 870! But I doubt it was an early one as I would have bought it if it was. I still have that plug on my bench!