We wanted an extremely compact semi-auto rifle that had 200+ yards stopping power was hearing safe with subsonic (inside 100 yards shot) rounds and pretty close with supersonic .300 Blk (to 200 yards+). With Barnes 110gr .300blk supersonic the solid copper bullets should expand out to almost 300 yards even in this 8" barrel.
Battle Arms Development's Vert PDW stock is perfect for a subcompact build like this but they couldn't say if it would run in .300 blk so we tested it to see for ourselves!