AAC Direct-Thread Adapters enable users of modular suppressors featuring industry-standard 1-3/8-24 threaded rear sockets to convert their suppressors to 5/8-24 direct-thread configurations. The AAC Direct-Thread Adapters are unobtrusive, low-profile designs that feature a muzzle-brake structure that divert gas and unconsumed propellant away from the projectile aperture and protects the blast chamber baffle from premature erosion. AAC Flange Indexing Direct-Thread Adapters feature a tool-featured flange with a square shoulder that indexes against the rear face of a host suppressor. Flange Indexing Direct-Thread Adapters should be compatible with most suppressors with industry-standard 1-3/8-24 threaded sockets.