- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Balloon-Head
Home > Propellants, Firearms, and Ammunition Development > Ammunition > Cartridge Cases > Balloon-Head
Farrington primer case
The next evolutionary step was the modern case. The rim of the balloon-head case was forged, rather than folded. It was stronger than the folded-head case and allowed the primer pocket to balloon into the powder space. This design gave the internal volume required for black powder. The rim cavity and the need for the high-stress fold at a critical point were eliminated. The head could fail when the case was very old, but critical rim blowouts were prevented. The balloon-head case continued to be used in some North American ammunition through the 1960s, typically in low-pressure revolver cartridges.
Solid head case
As smokeless propellants were developed, the volume issue was less important; the case could be further strengthened by filling in the area surrounding the primer pocket. This minor improvement (that began in high-pressure cases in the late 19th Century) is now commonplace in military and sporting cartridge cases. This modern design is called the solid-head case. When the balloon-head case was first developed, some ammunition companies referred to it as a solid-head case to emphasize the strength improvement over folded-head construction. Balloon-head is a modern term, coined to separate the current solid-head case from its immediate predecessor.
