I only have two English guns and the barrels of both appear to be uncut.

The barrels on my Joseph Lang are 27" and probably date from 1872 or a bit earlier (they're replacement barrels by James Woodward on a gun completed 6 March 1866).

The barrels on my J&W Tolley are 30" and this gun dates between 1887 and 1894.

I really have no idea what was "most popular".