I mean, I only said it could withstand a shovel's flat side and a good whack. I never tried shooting any glass, but I have personally had reason to whack a few tempered lites with a shovel when they wouldn't break and can personally attest to how surprisingly hard it can be compared to just chipping a corner against another piece of glass.

Another odd thing is that when two pieces chip at the corners, I've only ever seen one of them break. Somehow the other piece always seems to survive, though it normally gets scratched up enough that it's tossed out anyhow.