POTD: A .300 BLK Pistol Posted October 7, 2014 in AR-15, Photo Of The Day, Pistols with 9 CommentsTags: 300 BLK, ar-15, pistol Andy sent us the photo of his .300 AAC Blackout AR-15 pistol fitted with a stock arm brace. Bonus points for an original background (not a sofa or grass). Submit photos you have taken to TFB’s Photo Of The Day. Advertisement