Out of curiosity, did the glass shatter? I've seen a plate glass window that seemed to have been shot by a .22 but still held together.
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Tonight on Fox News, a judge who was in an adjacent office said the first thing he heard was glass shattering, then a "thud".
I took the "thud" to be the sound of the injured judge hitting the floor. (There would have been insufficient time between the window strike and the body strike for the ear to discriminate those two sounds -- especially amid the prolonged noise of falling glass fragments.)
If the .223 bullet's path was not absolutely perpendicular to the glass, the (relatively long) bullet would have immediately started to tumble -- which would have made the glass near the strike virtually 'explode'. (No recognizable bullet hole would remain...)