Last reviewed: 2026-04-19 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
For hunters working mountain elk, mule deer, or caribou across open country, the Sig Sauer Marksman Hunter 300 Winchester Magnum combines competition-level load consistency with field-proven Sierra GameKing construction. This 300 Winchester Magnum hunting ammo pushes a 165-grain jacketed hollow point to 3120 feet per second, generating 2566 foot-pounds at the muzzle — enough to anchor medium game cleanly inside 400 yards when you hold center-mass.
Built for the Box
Each round seats a Sierra GameKing boat tail hollow point — a design that reduces base drag, flattens trajectory, and resists wind deflection on cross-canyon shots. The thick jacket holds together through bone and shoulder blade; the skived bullet nose initiates expansion reliably at magnum velocities. Sig Sauer loads these cases to match-grade tolerances, giving you the consistency you need when you hike six miles for one opportunity. Boxer primers and reloadable brass let you work up custom loads once you’ve confirmed zero with factory ammunition.
The Numbers
| Spec | Value |
|---|---|
| Caliber | 300 Winchester Magnum |
| Bullet weight | 165 grains |
| Bullet type | Jacketed Hollow Point (Sierra GameKing) |
| Muzzle velocity | 3120 fps |
| Muzzle energy | 2566 ft-lbs |
| Ballistic coefficient (G1) | 0.363 |
| Rounds/box | 20 |
| Case | Brass, reloadable |
| Primer | Boxer |
| Corrosive | No |
| Lead-free | No |
| Intended use | Hunting (medium game) |
| Country of origin | USA |
The 0.363 ballistic coefficient holds velocity downrange better than flat-base designs, and the boat tail base minimizes yaw in crosswinds. Verify your rifle’s zero at 200 yards, then confirm drops at your maximum engagement distance before opening day. See more options in our 300 Win Mag ammo category.
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.
- Treat every firearm as if it is loaded; keep muzzle pointed in a safe direction at all times.
- This ammunition contains lead. Wash hands after handling. Pregnant women and children should avoid exposure. For California Proposition 65 information, visit www.P65Warnings.ca.gov.
- Ship to FFL-compliant addresses only; verify state and local restrictions before purchase.
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