Potator,
Definitely NOT
mint of
Rome.
Definitely NOT any of the three branch mints, clearly official, that produced large issues of
sestertii, and some middle bronze too, two of which Laffranchi pointed out in
his important article of 1948, while I discovered the third myself in my
work on Claudius, which began as a
Numismatic Chronicle review of von Kaenel's Münzprägung
des Claudius.
That is, a
Spanish mint, which furnished all of the
sestertii and
dupondii in the Pobla de Mafumet
hoard; a Gallic
mint, whose
sestertii were often
countermarked PROB; and a fine-style
mint, my discovery, perhaps located in the Po valley.
I think your As belongs to another major series, doubtless also official, which included mainly
asses. But I haven't really studied these series that don't include
sestertii.
There is an important article on Claudian bronzes of western
provincial style in
Revue Numismatique of around 2004, which might cover your coin. I have looked at the text online, but the plates are NOT online so I don't know what exact series and styles it deals with.
I think the major cause of the branch
mint production and imitations in bronze under Claudius was not
his invasion of
Britain in 43, but
his attempt to restrike as much of Caligula's coinage as possible in 41 AD. That's why virtually all of the branch-mint coins and imitations omit P P, so ought to have been produced before Jan. 42 when Claudius accepted that title.