Andro Corp 5" 5.56 Upper, A2 Flash Hider, 4" M-LOK Handguard, No BCG & CH - $251.16 after Code BARRELUP With a 5-inch barrel made of Chrome Moly Vanadium and a twist rate of 1-7, the 5.56 NATO AR-15 Upper from Andro Corp Industries offers dependable performance. It comes fitted with a sleek M-LOK