There's a tendency to use the word Bristol for anything with a green bowl, and it's probably a connection that's been borrowed from those late Georgian/Regency glasses, made usually with drawn funnel/trumpet and tulip shaped shaped bowls, with rather wide but flat feet - you'd recognize them - they're green throughout. Some may well have been made around Bristol, but doubtless a lot more were made in London and the Midlands, so probably dodgy to say Bristol definitely. Green bowls, apparently, were meant for port rather than wine.
With this piece perhaps not possible to be certain whether it's for wine, port or sherry - the Victorians made glasses for those drinks in a variety of shapes, and some even for water, although they'd be a little bigger probably. As you can imagine, dating lacks accuracy - Barry Skelcher is keen to date some hollow stemmed uranium examples to about 1870 - 1880, certainly not later than 1900 if the cut edges feel sharp - acid polishing produces smooth edges and means C20. The polished pontil depression is unreliable for dating in this instance, and my opinion is best to say 1870 - 1900, but if someone can be definite about earlier date then that's o.k.
He suggests that if the edge of the foot is symmetrically rounded then it's probably moulded and will date to post 1875 ish.
There are probably six flats on this stem - although seven is not uncommon.
This is a quality glass - if only you had the set. See attached pix for other second half C19 stems - plain and cut - I think the uranium example matches the pattern of your stem.