The Surefire M79 ring mount allows a 1 inch bodied light to attach to a Pic rail. The mount adjusts for rail variations because it uses a thumb screw on one side. The light body clamp portion also is somewhat adjustable to accomodate variations in light body diameter and personal preference for how tight the clamp closes. If your AK needs a rail system Ultimak makes one IIRC.
If all you have is a 12 o'clock rail, a side rail adapter by Warne allows you to mount the light to one side or the other of the top rail. On rifles where there is room to mount the light far enough forward, I tend to prefer a "wireless" 9 o'clock mounting and use my thumb on the rear tailcap switch.
The SF M78 or M79 allows the light to be quickly and easily attached or detached as needed, for handheld uses such as searching where you are not comfortable pointing the muzzle. Calvin at Brightflashlights supplied my M78 (executive sized bodies) and M79 (classic sized bodies) ring clamps. HTH.
Paladin