Systems and methods for coupling a barrel to a firearm are disclosed, including firearms incorporating the systems. In an embodiment, the firearm includes a receiver including a cavity and an internal thread disposed within the cavity. In addition, the firearm includes a barrel including a first threaded connector that is threadably engaged with the internal thread within the cavity and a second threaded connector. Further, the firearm includes a barrel nut including an internal thread and an external thread. The internal thread of the barrel nut is threadably engaged with the second threaded connector of the barrel.