it is a single shot cylinder (ie has only one bullet chamber), which why I got it at such a good price 50 euros, have now had a reply from the Tanfoglio factory in Italy,
Dear Mr. Forster,
we received your message and we thank you.
We don't produce the E151 single action revolver from 1994
and we don't have available any parts for this gun and it
is not possible to change the one shot cylinder with the
one with 6 shots.
So one Tanfoglio for sale !
Thanks everyone for you help.