Barrels are threaded on the outside to attach a suppressor.
Rifling is inside the barrel to spin the bullet.
Hold on there. If barrels aren’t threaded, how will forensic ballistic analysis work on a weapon that is fired? I do not have much knowledge on this subject.
That’s rifling, not threading. Threading is to attach a suppressor or break on the end of the barrel.
Barrels are threaded on the outside to attach a suppressor.
Rifling is inside the barrel to spin the bullet.