Machine guns having detachable barrels and methods of operating the same are disclosed. An illustrated example firearm includes a housing; a removable barrel; a latch to releasably secure the barrel in the housing, the latch having a released state and a secured state; and a carrying handle movable between a rest position and a carry position. The carrying handle cooperates with the latch such that the latch can only be moved into the released state to permit removal of the barrel when the carrying handle is at least substantially in the carry position.