I have a copy of an interesting book, Combat Loads (can't recall the author) who does a variety of testing on various calibers, rifles and ranges and reports the results in his book. Although I wouldn't call his approach scientific, his results were a bit of an eye opener.
For example, he reported that the .223 cartridge would not shoot through a concrete block (construction block). It made a tiny hole on one side and sprayed lead fragments on the other inside wall of the block.
Same problem shooting through a car door, few .223 rounds penetrated through the outer and inner skin. Even windshields can deflect this round.
No idea how a .223 round would work on glass block. If I recall correctly, you must exceed 2700 fps to retain fragmentation velocity. On shorter barreled rifles, this can be a problem. Using SS109 or some other steel core would give you better penetration results on hardened targets.
I'd get myself out to the desert and try this!