英语释义
1. a groove running lengthwise on the surface of a cylinder or column
2. a groove around the cylinder of an elongated bullet for small arms to contain a lubricant
3. a groove around a bullet into which the edge of the cartridge case is crimped
4. a groove around the rotating band of a gun projectile to lessen the resistance offered to the rifling
5. a groove around the base of a cartridge where the extractor takes hold