For what round is this chambered?
My first thought as well. I’m guessing it’s still the NATO 5.56 because of the availability.
5,56mm NATO, the SS109 or U.S. M855 round. The Tavorim I've fired had a barrel with a military 1:7 twist. The Tavor has a interchangable barrel in which only one mounting lug has to be disengaged which is on the right side of the weapon behind the pistol grip, maybe not quite as fast as an Australian AusSteyer or Austrian AUG, but removable/replacable within a minute or two.