This stood out among the jumble of gobbily gook.
Again, All i know is that on more than one occasion I put a burst into a car windshield coming up on our 6, only to watch the tracers (And ball) reflect right off the regular automotive glass.
(I know they wern't armored vehicles because the .308 from the 240 took care of the problem!)
I've shot more than a couple car windows with AK ammo since... no such issues.
...But what do I know...
As I noted previously, had you read all that "gobbily gook", M855 and M193 do not do the greatest against glass, hence the development of SOST.