AM-TAC Precision designed the .416 Hushpuppy to be the hardest hitting and flattest shooting subsonic cartridge ever available for the AR-15. It uses a 450 grain open tip match bullet and a short, stubby case to deliver a heavy hit from a cartridge that not only fits in standard AR-15s, it uses standard magazines (single stacked). It delivers a wound channel greater than 12 gauge shotgun buckshot or a 12 gauge slug thanks to its tail-heavy design which will begin to tumble when it hits.
Though it hits hard, it shoots more like a 20 gauge shotgun thanks to its subsonic velocity. The shooter feels more of a “thump” than a sharp blast. It has excellent suppression characteristics.
The photo shows a .223 bullet for comparison.