@DBM if you has the link of numisma article for this kind I will like to read. Theirs site is so ambiguate and hard to find something except some descriptions of coins. Maybe to big database.
Now I will explain why it is PRE Striking default, not error coin or PMD
I open a new roll of 25 cents from mint to verify the reedling. It is convex. The explanation of coin is that the reedling is soft on touch and almost flat.
I know the milling to day is double operation of milling and reedling. If the reedling rolls was at the end of life and the operator sleep, was change late.Second
: the reedling has Ni on the highest part and no abrasive traces. eliminate the polishing after strike. photo attached:Third
: The O and R of the coin show missing Ni on the low part of coin not only on the highest past=not happened before strike.Fourth
: To take out the Ni you need acid which will attack also the Cu. Here the scientific explanation:
Nickel metal dissolves slowly in dilute sulphuric acid to form solutions containing the aquated Ni(II) ion together with hydrogen gas.
Copper metal dissolves in hot concentrated sulphuric acid to form solutions containing the aquated Cu(II) ion together with hydrogen gas, H2. ... Copper metal also dissolves in dilute or concentrated nitric acid, HNO3.
I look at the default coins for the symptomatic prospectus of metallurgical and chemistry point of view.
Grading, value, rarity and collecting desire you guys are the experts not me.
If I am wrong with pleasure I will accept the reality. For me is interesting coin from the cheap production and quality control. But accept that is cos 3 or 4 cents to produce and put in the circulation.