Location of rifle scope reticle images?

[Yakavetta]

I want to make some new reticles for the rifle scopes, starting with the M24.  But when I open up "m24_crosshair_ca.paa" all I see is a couple of black boxes, or one big black box, depending on if I discard mipmaps or not.  Is this the right file to be editing, and if not which one is it?  I tried all of the M3A .paa's and the M24 .paa's.  Any help would be greatly appreciated.

I guess while I'm asking, what about the M107, Mk12, SVD and KVSK?

[Armored_Sheep]

2D weapon optics are done as models (p3d), asembling flat elements of the scope sight.