With Nikon's latest reticle and adjustment technologies, the M-223 integrates the same level of quality as the flagship Monarch riflescopes. Developed specifically for the trajectory of the .223 Rem/5.56mm NATO round with 55-grain polymer tipped bullet, the new BDC 600 reticle offers shooters unique open circle aiming points and hash marks from 100 to 600 yards. Ultra ClearCoat optical system delivers bright, sharp, and incredibly flat sight picture and light transmission. One-piece main body tubes provide minimum weight and maximum strength. Nitrogen-filled and o-ring sealed for waterproof, fogproof, and shockproof protection.