Via BBSpot’s mailing list, I discovered the Insultingly Stupid Movie Physics page. For example, this bit on movie-bullets:
The vast majority of bullets are made of copper-clad lead. They simply do not create sparks or visible flashes of light when they strike objects, even if the objects are made of steel. In the chemical industry it’s commonplace to limit maintenance workers to copper alloy or lead hammers when they are working in areas where flammable fumes may be present. Hammers made of these materials do not produce sparks when they strike objects, while steel hammers can. If you have never noticed this phenomenon don't be surprised, the sparks generally are barely visible even under ideal lighting conditions.