The Advanced Armament Corporation had their new Honey Badger on display at the AUSA expo. The PDW style AR-15 is chambered in .300 BLK AAC and features an ultra-short 6″ barrel and retractable stock. It is designed to be a quieter and more versatile substitute for the H&K MP5SD. It was designed with the subsonic .300 BLK loads in mind, but is a compatible with the more powerful supersonic loads.
[ Many thanks to TenPoundMonkey for photos and info. ]