Sat Sep 11, 2010 10:28 pm
The only way I could see a bullet doing that would be if the horn was made of cast metal, which it is obviously NOT. Or, if the steel had a major defect in it, also not likely. That metal is thick enough that anything short of a rifle round would just lightly dent it, and rifles punch nice, clean little holes in metal, anyway. Not big voids.
Rust is out, otherwise the whole thing would be falling apart. Even a combination of a large projectile (shotgun slug, maybe) and rust is far-fetched. There isn't even any bending that would be associated with a large projectile impact or an explosion.
Did the siren ever spend time on the ground or at a scrap yard during its life? That's the only other way I could see it getting damaged, but even then it seems it would have to be on purpose.
My money is on that chunk being removed deliberately. What for, who knows?