ACOG = Advanced Combat Optical Gunsights Advanced Combat Optical Gunsights (abbreviated ACOG) are a series of telescopic sights manufactured by Trijicon. The ACOG was originally designed to be used on the M16 rifle and M4 carbine, but Trijicon have also developed ACOG accessories for other firearms. Models provide fixed power magnification levels from 1.5Ã— to 6Ã—. ACOG reticles are illuminated at night by an internal phosphor. Some versions have an additional daytime reticle illumination via a passive external fiber optic light pipe. these sights are produce by Trijicon .. Cost nearly = 600 - 2000 USD, Depend upon type.. ======================= ======================= They main purpose of this thread to find alternatives of ACOG with P-rail attachments coz of the costs of ACOG.. @sayareakd Sir..