Delta Company Arms .300 BLK AR-15 and barrels Posted October 19, 2010 in AR-15, Rifles by Steve Johnson with No CommentsTags: .300 blk, 2010, ar, ar-15, rifle, rifles Delta Company Arms’s Custom AR-15 rifles are now available chambered in .300 BLK. Price depends on customer specifications. The company is also offering complete, headspaced barrels with extension for around $250USD. Win a Kel-Tec PMR-30 !!!