Last reviewed: 2026-04-19 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
The 300 WSM copper ammo from Winchester pairs a 180-grain solid copper polymer-tip projectile with a short magnum case, delivering 2950 feet per second and 3478 foot-pounds of energy at the muzzle. Engineered with a longer ogive and boat-tail profile, the Winchester Copper Impact bullet carries a G1 ballistic coefficient of 0.47 — flattening trajectory and reducing wind drift past 300 yards. The Extreme Point hollow cavity initiates immediate expansion on contact, creating a large wound channel while retaining near-100 percent of original bullet weight through shoulder bone and heavy muscle. Legal in California and other jurisdictions mandating lead-free projectiles, this load pairs monolithic copper construction with boxer primer and reloadable nickel-plated brass cases, shipping 20 rounds per box from United States manufacturing.
Performance Profile
Winchester builds the Copper Impact on a solid copper mono-metal platform, eliminating core separation and jacket peel common to cup-and-core designs under high-velocity impact. The polymer tip drives hydraulic pressure into the Extreme Point hollow cavity, initiating petal formation within the first two inches of penetration. At 300 Winchester Short Magnum velocities — 2950 fps from a 24-inch barrel — the 180-grain projectile maintains supersonic flight past 1,000 yards, carrying 1,800 foot-pounds of energy to 400 yards for reliable expansion on elk vitals. The boat-tail base and extended ogive reduce drag, yielding a trajectory 3 inches high at 100 yards, 3 inches low at 250 yards with a 200-yard zero. Nickel-plated cases resist corrosion in humid climates and cycle reliably through magnum-length actions.
| Spec | Value |
|---|---|
| Caliber | 300 Winchester Short Magnum (WSM) |
| Bullet weight | 180 grains |
| Bullet type | Winchester Copper Impact Polymer Tip |
| Muzzle velocity | 2950 fps |
| Muzzle energy | 3478 ft-lbs |
| G1 BC | 0.47 |
| Rounds/box | 20 |
| Case | Nickel-plated brass |
| Primer | Boxer |
| Corrosive | No |
| Lead-free | Yes |
| Reloadable | Yes |
| Intended use | Hunting |
| Manufacturer | Winchester |
Hunters running short-action magnums in Winchester Model 70, Browning X-Bolt, or Tikka T3x platforms will find the 180-grain Copper Impact balanced between sectional density and velocity — sufficient for penetrating heavy shoulder structure on bull elk while maintaining flat trajectory for pronghorn at 350 yards. Explore the full 300 WSM ammo inventory for comparable jacketed and monolithic loads.
Safe Handling & Compliance
Federal law requires purchasers to be at least 18 years old for rifle and shotgun ammunition, and at least 21 for handgun ammunition. Ammunition cannot be shipped to certain states, counties, and cities — review our ammunition shipping restrictions before ordering. Store ammunition in a cool, dry location away from heat sources and out of reach of unauthorized users.
- Observe the four universal rules: treat every firearm as loaded, never point at anything you are not willing to destroy, keep your finger off the trigger until ready to fire, and know your target and what lies beyond it.
- Verify that your firearm is chambered for 300 Winchester Short Magnum before loading — do not confuse with 300 Winchester Magnum (longer case).
- California Proposition 65: This product contains materials known to the State of California to cause cancer and reproductive harm. Wash hands after handling ammunition and components. Use adequate ventilation when shooting indoors or in enclosed ranges.
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