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Copper Alloy

C260 Cartridge Brass

C260 cartridge brass is the classic 70/30 copper-zinc alloy optimized for cold forming rather than machining. Its outstanding ductility (45% elongation) and balance of strength (370 MPa) make it the premier deep-drawing brass, famously used for ammunition cases. Good corrosion resistance (4/5) and an attractive finish round out its appeal.

How C260 Cartridge Brass machines

Rated 3.5/5, decent but well below leaded C360. Without lead it's tougher and gummier, producing longer chips and more built-up edge, so it cuts more like a ductile copper alloy. Use sharp tools and moderate speeds. C260 is chosen for its formability, not turning; for machined parts pick C360 instead.

Manufacturing & processing

Listed for sheet-metal work, and that's its strength, it excels at deep drawing, stamping, bending, and spinning. It cold-works to higher strength and can be annealed between draws to restore ductility. Solders and brazes well. Watch for season cracking (stress-corrosion) in high-zinc brass; stress-relieve drawn parts to avoid cracking in ammonia-bearing environments.

Typical applications

Ammunition cartridge cases, the namesake use; deep-drawn cups, shells, and enclosures; lamp and hardware components; decorative and architectural trim; plumbing and electrical formed parts. Chosen wherever a brass part is produced by drawing, stamping, or bending rather than machining.

When to choose it

Choose C260 when the part is deep-drawn, stamped, or formed and needs high ductility with good corrosion resistance and appearance. If the part is machined in volume, C360 cuts far faster. If you need higher strength or spring properties, look at phosphor bronze (C510).

Suitable surface finishes

Common finishes for C260 Cartridge Brass: nickel plating, chrome plating, electropolishing, brushed. Use the finish selector →

FAQ

Why is C260 called cartridge brass?
Its 70% copper / 30% zinc composition gives the best combination of strength and ductility for deep drawing, which is exactly what's needed to form ammunition cartridge cases from a flat blank. The name stuck because that high-volume application defined the alloy's optimization toward formability.
What is season cracking and how do I prevent it?
Season cracking is stress-corrosion cracking in high-zinc brass: residual forming stresses plus a corrosive agent (notably ammonia) cause spontaneous cracking over time. Prevent it by stress-relief annealing drawn parts (a low-temperature bake) to remove residual stress before service in such environments.
Should I machine or form C260?
Form it. C260 is optimized for cold forming, deep drawing, stamping, and bending, where its 45% elongation shines. Its 3.5/5 machinability is mediocre because it lacks the lead of C360. If your part is primarily machined, switch to free-cutting C360; reserve C260 for formed geometries.

Property values are typical/nominal for early guidance and vary by temper, grade, supplier and heat treatment. Confirm critical specs against a certified datasheet or with an mfgiq engineer.