Copper Alloy Bullet Jacket Cups

B131-12: Standard Specification for Copper Alloy Bullet Jacket Cups

For engineers and manufacturers in the defense and ammunition sectors, ensuring the integrity and performance of projectile components is paramount. ASTM B131-12, the "Standard Specification for Copper Alloy Bullet Jacket Cups," provides an essential framework for the procurement and quality control of these critical preforms, ensuring reliability and consistency in a demanding industry.

What is B131-12?

ASTM B131-12 is an authoritative standard that defines the material properties, manufacturing requirements, and quality control measures for copper alloy cups intended for the fabrication of bullet jackets. Originating from ASTM Committee B05 on Copper and Copper Alloys, this specification ensures that these preforms meet precise technical criteria for successful downstream processing into ammunition components.

Scope & Purpose

This comprehensive standard governs the production of bullet jacket preform cups made from Copper Alloy UNS No. C22000. It specifies requirements for various caliber types and classes, including options for annealed and non-annealed states. The standard focuses on the cup's material composition, grain size (for annealed tempers), dimensional tolerances, and freedom from defects that could compromise its subsequent forming into a finished bullet jacket. It does not cover the final bullet jacket manufacturing process itself.

Who Must Comply?

• • Primary audience: Materials Engineers, Metallurgists, Quality Control Inspectors, Manufacturing Engineers, and Procurement Specialists involved in ammunition component production.
• • Industries affected: Defense, Ammunition Manufacturing, and potentially Aerospace industries where specialized projectile components are utilized.
• • Compliance nature: Typically voluntary, but often mandated by contract specifications and purchase orders for government and commercial defense procurement.
• • Enforcement: Compliance is generally verified through supplier certifications, internal quality control processes, and third-party inspections as stipulated in contracts.

Key Requirements Overview

Professionals working with B131-12 must adhere to several core provisions to ensure product conformity:

• • Material Composition: The standard requires that cups be manufactured from Copper Alloy UNS No. C22000, with specific limits for elements like copper, lead, iron, and bismuth, while zinc constitutes the remainder.
• • Manufacturing Process: Manufacturers must ensure cups are formed from annealed plate, sheet, strip, or disks, and processed to achieve uniform cup geometry suitable for subsequent drawing operations. Annealed cups must be cleaned to facilitate further fabrication.
• • Grain Size Control: For annealed cups (Class II), specific average grain size ranges (e.g., OS025 or OS040 tempers) are mandated, crucial for material ductility and formability.
• • Dimensional Accuracy: Cups must conform to specified dimensions and tolerances as detailed on contract drawings, ensuring proper fit and function in automated manufacturing lines.
• • Workmanship and Finish: The standard mandates that cups be free from defects such as deep scratches, laminations, cracks, or wrinkles that could impede their intended use as bullet jacket precursors.

Related Standards & References

ASTM B131-12 is often used in conjunction with other ASTM standards to provide a complete picture of material and product requirements. Complementary standards include:

• • ASTM B601: Classification for Temper Designations for Copper and Copper Alloys, providing standardized temper nomenclature referenced for