I'm a bit confused by the question, usually in the context of rifles and handguns a threaded barrel refers to external threads on the muzzle end for attaching suppressors or other thread-on muzzle devices. Most include some kind of thread protector as well. Sorry if I am way off base of what you are asking, here's a good image of the threaded end of one: blackanklemunitions.com/wp/wp-content/uploads/2018/11/SCOAC861_1.jpg

What does a threaded barrel look like? Just think about opening a 2 liter bottle of soda. When you unscrew the cap that's basically what it looks like. Well, sort of. But you should get the idea.

Tara, a threaded barrel has threads on the muzzle of the barrel to screw on muzzle brakes, suppressors etc. Apicture is here : google.com/search?q=threaded+barrel&sxsrf=ACYBGNQehgwP1xd1kAb2HJlbXIgRoLbSUQ:1578316924567&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjKzIbdiO_mAhUrUt8KHcttDSoQ_AUoAnoECBEQBA&biw=1920&bih=966#imgrc=vnBFXqoyI69zsM:

here is a picture most have a cap over the threads when a muzzle device is not installed https://silencerco.com/threaded-barrel.html