Last reviewed: 2026-04-19 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
For hunters pushing .30-caliber magnums past 400 yards, the Underwood 300 Winchester Magnum 165-grain Nosler AccuBond load combines high sectional density with bonded-core construction. This is 300 Winchester Magnum ammo engineered for controlled expansion and deep penetration on elk, moose, and bear-sized game. The 165-grain AccuBond exits the muzzle at 3300 feet per second, carrying 3990 foot-pounds of energy—enough to flatten trajectory and buck wind without sacrificing terminal performance. Underwood Ammunition loads this round in nickel-plated brass cases with Boxer primers, making spent brass reloadable for handloaders who want to tune velocity or experiment with seating depth.
Load Profile
The Nosler AccuBond bullet uses a polymer tip to initiate expansion on impact while the bonded core—a proprietary process that fuses the copper-alloy jacket to the lead core—prevents jacket-core separation during penetration. In gel tests, AccuBond projectiles retain 60-70% of their original weight and mushroom symmetrically, even after punching through heavy shoulder bone. The 0.475 G1 ballistic coefficient keeps this 165-grain bullet supersonic past 1,000 yards at sea level, and the 0.248 sectional density ensures adequate penetration on quartering shots. Nickel-plated cases reduce friction during feeding and resist corrosion in humid climates or saltwater environments.
The Numbers
| Spec | Value |
|---|---|
| Caliber | 300 Winchester Magnum |
| Bullet Weight | 165 Grains |
| Bullet Type | Nosler AccuBond Polymer Tip |
| Muzzle Velocity | 3300 Feet Per Second |
| Muzzle Energy | 3990 Foot Pounds |
| G1 Ballistic Coefficient | 0.475 |
| Sectional Density | 0.248 |
| Rounds Per Box | 20 |
| Case | Nickel Plated Brass |
| Primer | Boxer |
| Corrosive | No |
| Reloadable | Yes |
| Lead Free | No |
| Intended Use | Hunting |
| Manufacturer | Underwood Ammunition |
Underwood field-tests every load in real firearms before release, using the same rifles hunters carry in the field. This 165-grain AccuBond load is optimized for bolt-action rifles with 24-26 inch barrels and standard SAAMI chambers. For more options in this caliber, browse our full selection of 300 Win Mag ammo.
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 the muzzle pointed in a safe direction at all times.
- Verify ammunition matches the caliber stamped on your rifle’s barrel and chamber before loading.
- This product contains lead. Wash hands thoroughly after handling ammunition or cleaning firearms. Pregnant women and children should avoid exposure to lead dust and residue.
Reviews
There are no reviews yet.