I have a "Jungle Gun", made by Army Navy, Webley "Screw Grip" action 28" barrels, about 7 3/4 lbs. Probably the oddest rifling I've ever seen. Wide lands and grooves STRAIGHT about 21" and then a very slight twist to the right the last four inches. 19 grains of Unique and a Paradox style bullet, 2" at 50 yards, I can't see to 100...
The tern "Jungle Gun" was often used to describe "Ball Guns", large bore shotguns with no rifling. Only Army Navy signs their guns Jungle Gun.. I also possess a Cosmos and Paradox, which are all in the category of "Ball and Shot guns" which all have some type of rifling, be it, Ratchet, Invisible, Oval or the screwy one on my Army Navy.
JZ