Lost Thread - Per Material Projectile Emitter

Usually don't do this, because I'm pretty good at finding threads and resouces with the search engine, but I just can't seem to find one posted several days ago about per material emitter/projectile animations and sounds.
It include a link to a short video of a pistol being fired into metal and glass surfaces. (I certainly hope it was in these forums and not TGC or somewhere else!)
If anyone remembers that thread or has the link I'd really appreciate it. I've been formulating "projectile, material, sounds, emitters, per, " etc. and every variation with no luck.
Thanks,

- Alan