A firearm suppressor mounting device has a body defining a body bullet passage on a bore axis and having a first attachment facility at a first end, the first attachment facility adapted to connect to the muzzle of the firearm, the body having a second attachment facility, a device adapted to removably and rotatably connect to the second attachment facility, a retention facility connected to the body and movable between an engaged position in which the retention facility abuts the device and a disengaged position in which the retention facility is spaced apart from the device, and each of the retention facility and the device having a plurality of engagement features that are engaged to each other to prevent rotation of the device with respect to the body when the retention facility is in the engaged position. The retention facility may encircle the bore axis.