You are partly mistaken but yes the cup is Russian and made in Moscow but the assayer is not HC who is the maker. Unfortunately it is rather difficult to tell who the maker is because there are a few alternatives. According to the law it was forbidden to use the same makers initials in a punch at the same time in the same town. Unfortunately this law was not always obeyed and this usually the result; so who is it?
Mind my asking but are there any marks on the handle?
The assayer is AC (Latin AS) that is Aleksandr Smirnoff in Moscow. He was active 1857-1895.
You wrote that you have recently started to be interested in Russian silver. Take my advice and do not buy anything if you don't understand the markings i.e punches, their location and what the mean etc.. Unfortunately the market (especially internet) is crowded with fakes. Buying a fake can can turn out to be costly mistake. Who wants that?
This is a rather good start:
https://www.925-1000.com/Frussia.html