HS503GPrimary Arms and Holosun have combined forces to bring you the power of the patent pending ACSS CQB reticle in a red dot sight for the first time! The problem with dot sights is that a large dot is great up close but less useful at distances beyond 100 yards, because the dot becomes too large to aim with precision. A small dot used in conjunction with a magnifier fixes that problem, but is slower to acquire in close range snap shooting. The ACSS