It's approximately Civil War period, mid 19th century. The earlier the pipe, the smaller the bowl. It was because tobacco was so expensive. By the end of the 18th century the pipe bowl size had gotten much larger, and your jumbo sized one was used mid 19th century when there was an ample supply of tobacco.
There appears to be a mould mark on the heel of the bowl, but it's terribly out of focus. With a better, sharper picture we might be able to attribute and date it more precisely.
Good picture. JG within a studded circle, was the mark for Jean Gambier (succeeded in 1817 by his son Joseph) of Givet in Northern France, although they later had offices in Paris and London plus agents in the US.
They were founded in 1780 and, although first use of that mark was claimed to be c1794, it wasn’t registered until 27th November 1877. Minervin Hasslauer bought the factory from Joseph Gambier in 1835 and the 1877 registration was filed by Jules Emile Proteau on behalf of Hasslauer and De Charnpeaux (who ultimately took over the business completely). The factory finally closed in 1926, having been in decline since about 1870.
Between 1850-1926 they made an estimated 2 billion pipes in numbers peaking at 300,000 a day in the mid-1800s, many of which went for export. In later years they concentrated mainly on ornate and famous personality character-head pipes in an effort to fend of competition from wooden pipes and cigarettes. I would put this pipe exactly where smokeythecat put it… around 1840-1870 although it could be a little earlier or later.