Hunting construction
Soft-point, bonded, partitioned, and monolithic expanding bullets are designed differently. Their intended impact-velocity ranges and use cases come from the bullet or ammunition manufacturer.
THE CARTRIDGE LIBRARY · SPORTING & MATCH RIFLE
.300 Weatherby Magnum
A belted .30-caliber magnum with the Weatherby double-radius shoulder profile. Its load-specific velocities depend on the actual test barrel.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Overall · min–max
- 3.390–3.560 in
86.106–90.424 mm - Case length · max
- 2.825 in
71.755 mm - Bullet maximum
- 0.3083 in
7.831 mm - Rim diameter · max
- 0.5315 in
13.500 mm
Know the exact name
At a glance
- Cartridge family
- Sporting & match rifle
- Bullet specification
- 0.3083 in / 7.831 mmBullet maximum
- Factory examples
- 9 loadsSelected, sourced examples below
- Weight in cited examples
- 165–200 grGrains measure mass, not powder charge
.300 Weatherby Magnum is identified by its complete cartridge designation. The resource-table alternative is 300 Wby Mag. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
It is a different cartridge from .300 Winchester Magnum. Weatherby model estimates on this page do not represent additional firing tests.
Dimensions: open the exact dimensional drawing ↗. The displayed number is bullet maximum, rather than an assertion that every manufactured projectile or barrel has this exact diameter.
Origins & evolution
Background & development
Roy Weatherby developed the .300 Weatherby Magnum in 1944 from the .300 Holland & Holland case family. His design reduced body taper and used the double-radius shoulder that became one of the visual signatures of Weatherby cartridges. The objective was greater capacity and velocity within a purpose-built high-performance sporting system.
The timing mattered. The design appeared as slower-burning propellants became increasingly available, helping make large-capacity sporting cartridges commercially practical. The .300 became one of the best-known expressions of Weatherby’s hunting-rifle philosophy and remained closely associated with his rifles and ammunition. Later .30-caliber magnums exceeded or challenged particular aspects of its performance, but its historical influence predates those contests. It represents the early Weatherby period, when a custom-rifle business and a distinctive family of cartridges grew together around high-velocity big-game hunting.
Historical sources: Sierra: .300 Weatherby Magnum cartridge history ↗
Construction changes the story
Loads, variations & specialty offerings
Match construction
Open-tip match and tipped match bullets prioritize consistency and aerodynamics. A match designation does not by itself mean the projectile was designed for hunting expansion.
Specialty offerings
Lead-free, reduced-recoil, and premium long-range products are separate load designs when offered. Compare the exact SKU, bullet weight, test barrel, and intended role rather than relying on a cartridge-wide average.
In the cited .300 Weatherby Magnum examples, bullet weights are 165, 180, 200 grains. These are the weights actually present in this source selection, not a claim that every possible loading is listed.
Bullet construction background: Hornady: anatomy of a bullet ↗. Exact product descriptions and velocities are cited in the factory table.
From the factory catalog
165 grains
3,390 fps
Interlock
180 grains
3,100 fps
CX®
200 grains
2,960 fps
ELD-X®
Compare all 9 cited factory load records
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| WeatherbyH300165IL | 165 gr 10.69 g | Interlock | 3,390 fps 1,033 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| WeatherbyN300165BST | 165 gr 10.69 g | Ballistic Tip | 3,350 fps 1,021 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| Hornady822124 | 180 gr 11.66 g | CX® | 3,100 fps 945 m/s | Not stated here; see source | Hornady · PDF p. 187 ↗ |
| WeatherbyB300180TTSX | 180 gr 11.66 g | Barnes TTSX | 3,232 fps 985 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| WeatherbyH300180IB | 180 gr 11.66 g | Interbond | 3,240 fps 988 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| WeatherbyH300180IL | 180 gr 11.66 g | Interlock | 3,240 fps 988 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| WeatherbyN300180ACB | 180 gr 11.66 g | Accubond | 3,250 fps 991 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
| Hornady82213 | 200 gr 12.96 g | ELD-X® | 2,960 fps 902 m/s | Not stated here; see source | Hornady · PDF p. 187 ↗ |
| WeatherbyH300200ELDX | 200 gr 12.96 g | ELD-X | 3,000 fps 914 m/s | 26 in | Weatherby · PDF p. 2 ↗ |
Explore the published data
Ballistics you can inspect
Select a legend entry to add or remove its line. Hover or tap a plotted point, or use the position slider. With the graph focused, arrow keys move the inspector. Solid dots identify source points; dashed connectors show estimates between them. Load construction, pressure category, and test setup can differ even at the same grain weight.
Read the original values as accessible tables
.300 Weatherby Magnum: estimated shorter-barrel scenarios
| Exact load | Source | Published points |
|---|---|---|
| 165 gr Interlock · 30 fps/in scenario | Weatherby 2020 rule; calculated scenario | 16: 3090; 17: 3120; 18: 3150; 19: 3180; 20: 3210; 21: 3240; 22: 3270; 23: 3300; 24: 3330; 25: 3360; 26: 3390 |
| 165 gr Interlock · 65 fps/in scenario | Weatherby 2020 rule; calculated scenario | 16: 2740; 17: 2805; 18: 2870; 19: 2935; 20: 3000; 21: 3065; 22: 3130; 23: 3195; 24: 3260; 25: 3325; 26: 3390 |
.300 Weatherby Magnum: factory velocity downrange
| Exact load | Source | Published points |
|---|---|---|
| 165 gr Weatherby Interlock | Weatherby | 0: 3390; 100: 3123; 200: 2873; 300: 2636; 400: 2411; 500: 2197 |
| 180 gr Hornady CX® | Hornady | 0: 3100; 100: 2893; 200: 2696; 300: 2507; 400: 2326; 500: 2152 |
| 200 gr Hornady ELD-X® | Hornady | 0: 2960; 100: 2804; 200: 2652; 300: 2505; 400: 2363; 500: 2225 |
| 165 gr Weatherby Ballistic Tip | Weatherby | 0: 3350; 100: 3133; 200: 2927; 300: 2730; 400: 2542; 500: 2361 |
| 180 gr Weatherby Barnes TTSX | Weatherby | 0: 3232; 100: 3025; 200: 2827; 300: 2638; 400: 2457; 500: 2283 |
| 180 gr Weatherby Interbond | Weatherby | 0: 3240; 100: 3031; 200: 2832; 300: 2642; 400: 2460; 500: 2285 |
| 180 gr Weatherby Interlock | Weatherby | 0: 3240; 100: 3005; 200: 2782; 300: 2570; 400: 2368; 500: 2175 |
| 180 gr Weatherby Accubond | Weatherby | 0: 3250; 100: 3051; 200: 2861; 300: 2678; 400: 2503; 500: 2335 |
| 200 gr Weatherby ELD-X | Weatherby | 0: 3000; 100: 2840; 200: 2687; 300: 2538; 400: 2394; 500: 2255 |
How to interpret the comparison
Changing bullet weight also often changes bullet design and propellant choice. Two curves are comparisons of the listed products, not a controlled experiment proving that bullet weight alone caused the difference. Catalog downrange points are projections under the maker’s conditions; barrel-study points are recorded observations in the study firearm.
Direct answers
Common questions
What is .300 Weatherby Magnum?
A belted .30-caliber magnum with the Weatherby double-radius shoulder profile. Its load-specific velocities depend on the actual test barrel.
What diameter does .300 Weatherby Magnum use?
The cited dimensional standard lists 0.3083 inches (7.831 mm), bullet maximum. This drawing convention is different from a casual caliber nickname.
Are similarly named cartridges interchangeable?
It is a different cartridge from .300 Winchester Magnum. Weatherby model estimates on this page do not represent additional firing tests.
Are the graph values measured or estimated?
The downrange view uses the exact manufacturer catalog records shown in the source table. The estimated barrel-length view applies the disclosed Weatherby slope rule to the 26-inch catalog anchor; it is a calculated scenario. Dashed connectors and intermediate inspector values use linear interpolation between the displayed source points. Calculated energy uses the listed bullet mass and velocity.
Does higher energy mean the best load?
Energy is calculated from mass and velocity. It does not establish accuracy, expansion, penetration, pattern density, recoil, or suitability for a particular firearm. Use the exact product documentation and firearm manual.
Trace the facts
Sources & methodology
Compiled by 2A Ledger from the linked standards, manufacturer publications, and identified test records. Checked October 18, 2026. Historical tests and older catalogs retain their original dates; a listing here does not establish current availability.
- SAAMI: dimensional drawing · PDF p. 124 ↗
- Sierra: .300 Weatherby Magnum cartridge background ↗
- Weatherby · PDF p. 2 ↗
- Hornady · PDF p. 187 ↗
Diameter figures preserve the cited drawing convention. Inch–millimeter conversion uses exactly 25.4 mm per inch. Factory specifications describe the maker’s test setup; your firearm, ammunition lot, temperature, and measuring method can produce different results. This is an educational factory-ammunition reference, not a reloading manual.