- 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
Materials and Methods
Home > Modern Firearms Manufacture > Gross Metal Forming Operations > Die Casting > Materials and Methods
Although other metal-casting processes are used in firearms manufacture, sand casting and investment casting are the most prevalent methods for ferrous alloys. Investment casting has all but replaced sand casting; older guns with sand-cast parts are still in circulation.
In the past two decades, there has been a considerable increase in the use of polymer plastics for major firearms components. In the past, plastic was used for nonstressed parts like butt plates, grips, and trigger guards. Handguns with high-strength polymer frames are commonplace.
Injection molding is the process for making precise plastic parts. Melted plastic under pressure is forced into a preheated mold. While the part is still in the mold, chilled water flushes through channels within the mold to set the surface of the plastic quickly. For dimension-critical parts, such as frames, the part is left in the mold for a time to allow uniform cooling without warping.
