RM400-16B-C View cart “Sig M400 AR-15 5.56/223 Carbine 16″ Barrel 30 Rd mag” has been added to your cart. Showing the single result Default sorting Sort by popularity Sort by average rating Sort by latest Sort by price: low to high Sort by price: high to low Sale! IN STOCKSig M400 AR-15 5.56/223 Carbine 16″ Barrel 30 Rd mag $849.99 Original price was: $849.99.$764.99Current price is: $764.99. Add to cart