In for info. ACOGs get me confused as well. There are so many of them.
Well the two listed above are spec'ed for the Marines. It's what they wanted and that's what Trijicon made. My best guess on the others is if it says M16 it's set up for a 20" barrel, M4 = 14.5" and if it doesn't say either I would bet it's perfect for a 16". Again it's just my best guess.Steve K said:Yeah. That's more or less what I though, but what about the ACOGs that do not mention barrel length? Are they set up for 16''? If that's the case, would it really effect the BDC of a 20'' barrel enough to justify getting the dedicated 20'' ACOG?