I have seen the video on the Trijicon website about how the BAC principle works. It seems to me to be based on how the human eye and brain work more than some feature on a scope.
Is there something different about an ACOG that lends itself to this type of aiming more than a 2X or magnified Aimpoint?
What is the ACOG bringing to the table that makes it unique in terms of BAC?
coming up with it first?
First off, the BAC or Bindon Aiming Concept only refers to fiber-optic ACOG’s as they have a bright enough reticle (like a red-dot). The Bindon Aiming Concept refers to the eyes when both are open not seeing the magnification until you stop and hold the scope on the target. This is when your eyes and brain pick up the magnification. When acquiring a target the weapon and scope is moving fast enough so that your eyes and brain do not pick up on the magnification but only the bright reticle and the target. With enough training/practice you could get good enough to use your fiber-optic ACOG as a red-dot for CQB distances and longer-range precision distances.
They were the first ones to name it.
Gly Bindon is the founder of Trijicon, thus Bindon Aiming Concept.
The concept, at it’s core, is shooting a magnified optic with both eyes open.
As we know, when you move a magnified optic with any kind of speed the image is blurred to the eye behind the optic. Now think about OEGs (occluded eye gunsights). There is no usable image other than the readily apparent dot.
So if you put a readily seen reticle into a magnified optic you can track a target using the eye that is out of the optic while having an OEG aiming point. All that is required is a reticl that is obvious enough to stand out from the blur, another eye, and enough binocular vision to marry the two images.
It is usable as an engagement technique at ranges close enough that the normal divergence in the eyes’ line of sight when not viewing the same image is not a huge factor, as well as at longer ranges to track the movement of a target until it stops or slows enough to focus through the magnification.
The more obvious the reticle the easier it is to do, though it is applicable with practice even with standard non-illuminated reticles provided the reticle is thick enough to be tracked.
It is not really a CQB technique. That method is more similar to the OEG technique since the shooter will probably not be able to use a 4X magnification to achieve good sight picture on a threat at 10 yards due to the small target area visible through the optic.
As I understand it, BAC is simply the use of occluded gunsight concept on a zoom optic.
The only part of this that’s unique to the ACOGs is the brightness of the dual-illuminated models making the illuminated part of the reticle very hard to miss in most lighting conditions.
The same concept applies with optics like the MR/T or ShortDot, but only with illuminated reticle ON and at the appropriate brightness. The ACOGs are unique in that the reticle is supposed to be used while very bright.