Reliable 300 WSM reloading data is published by major manufacturers including Hodgdon, Hornady, Nosler, and Sierra. Published load recipes normally include the specific 0.308-inch bullet, powder type, starting and maximum charge weights, expected muzzle velocity, and cartridge overall length. Common bullet weights covered by published 300 WSM load data range from 150-grain hunting projectiles up to heavy 212-grain match bullets. Results naturally vary between sources due to differences in bullet profile, exact powder burn rates, brass case capacity, primer type, test barrel length, and atmospheric testing conditions.
300 WSM Reloading Data
| Bullet | Bullet Weight | Powder | Published Starting Load | Published Maximum Load | Published Velocity | Pressure (Max) | Primer & Case | Cartridge Overall Length (COL) | Barrel Length / Firearm | Source |
| Hornady SST | 150 grain | Hodgdon Varget | 54.0 gr | 59.5 gr | 3,248 fps | 63,400 PSI | Large Rifle Mag / Win | 2.800″ | 24.00″ / Universal | Hodgdon |
| Nosler AccuBond | 165 grain | Hodgdon H4350 | 61.0 gr | 65.5 gr | 3,114 fps | 63,800 PSI | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hodgdon |
| Barnes TSX | 165 grain | Alliant RL-17 | 61.0 gr | 65.0 gr | 3,120 fps | Not Listed | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Alliant |
| Sierra SBT | 180 grain | Hodgdon H4350 | 59.0 gr | 63.5 gr | 2,950 fps | 63,500 PSI | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hodgdon |
| Hornady InterLock | 180 grain | Winchester 760 | 58.0 gr | 64.0 gr | 2,930 fps | 63,900 PSI | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hodgdon |
| Nosler Partition | 200 grain | Hodgdon H4831SC | 59.0 gr | 63.5 gr | 2,750 fps | 63,100 PSI | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hodgdon |
| Hornady ELD-X | 200 grain | Alliant RL-22 | 58.0 gr | 64.1 gr | 2,820 fps | Not Listed | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hornady |
| Hornady ELD Match | 212 grain | Hodgdon Retumbo | 59.6 gr | 64.9 gr | 2,720 fps | Not Listed | Large Rifle Mag / Win | 2.860″ | 24.00″ / Universal | Hornady |
Understanding The 300 WSM Reloading Data
To safely develop a 300 WSM load recipe, handloaders must understand the specific variables that govern this short, wide-bodied magnum cartridge:
- Starting load: The minimum safe powder charge. Reloaders must always begin load development here to safely establish a baseline before working up.
- Maximum published load: The absolute safe powder limit established by a ballistic laboratory. Exceeding this limit will cause dangerous overpressure, leading to blown primers and heavy bolt lift.
- Velocity: The bullet speed in feet per second (fps) measured at the muzzle. The 300 WSM was specifically designed to match .300 Winchester Magnum velocities while utilizing less powder.
- Pressure: The 300 WSM is authorized by SAAMI to operate at a maximum average pressure of 65,000 PSI.
- Bullet weight: The mass of the 0.308-inch projectile in grains.
- Powder: The specific propellant type. The cartridge requires medium-slow to slow-burning rifle powders to maximize performance.
- Barrel length: Test barrels for the 300 WSM are universally 24 inches in major load manuals.
- Firearm used for testing: Universal receiver test barrels or production bolt-action rifles.
- Test conditions: Altitude, humidity, and temperature variables during pressure testing.
- Cartridge overall length (COL): The total length of the loaded cartridge. The 300 WSM is engineered to fit into a short-action rifle, strictly dictating a maximum COL of 2.860 inches.
Different published sources may produce varying results because they utilize brass cases with different internal volumes (e.g., Winchester vs. Norma brass), different primer brands, and varying tight-tolerance test chambers.
300 WSM Bullet Weight Reloading Data
The 300 Winchester Short Magnum utilizes standard 0.308-inch diameter bullets, granting reloaders access to one of the largest selections of hunting and match projectiles in the world.
- 150 grain: Lightweight options that produce relatively mild recoil. Driven to speeds exceeding 3,200 fps, these bullets provide incredibly flat trajectories for medium game like whitetail deer and antelope.
- 165 grain to 168 grain: A highly popular intermediate weight. The 165-grain AccuBond or 168-grain MatchKing strike an excellent balance between high velocity (often exceeding 3,100 fps) and wind resistance, making them ideal for long-range target shooting and mule deer hunting.
- 180 grain: The traditional standard for elk and moose. The 300 WSM comfortably pushes 180-grain bullets to 2,950 fps, matching the classic performance of the full-length .300 Winchester Magnum.
- 200 grain to 212 grain: The extreme heavyweights. Because the 300 WSM is restricted by a 2.860-inch short-action magazine length, these exceptionally long, high-BC bullets must be seated deeply into the case. This intrudes on the powder column and reduces case capacity, but they remain highly effective for extreme long-range (ELR) shooting.
Do not assume a 180-grain monolithic copper bullet uses the exact same powder charge as a 180-grain lead-core bullet. Solid copper bullets (like the Barnes TSX) are longer and create more bore friction, requiring specialized load data to maintain safe pressure curves.
300 WSM Powder Reloading Data
The 300 WSM features a short, fat powder column and a sharp 35-degree shoulder, providing highly efficient combustion. It excels with medium-slow to slow-burning extruded and spherical rifle powders.
| Powder | Bullet | Bullet Weight | Published Starting Load | Published Maximum Load | Published Velocity | Source |
| Hodgdon H4350 | Nosler AccuBond | 165 grain | 61.0 gr | 65.5 gr | 3,114 fps | Hodgdon |
| Hodgdon H4350 | Sierra SBT | 180 grain | 59.0 gr | 63.5 gr | 2,950 fps | Hodgdon |
| Alliant RL-17 | Barnes TSX | 165 grain | 61.0 gr | 65.0 gr | 3,120 fps | Alliant |
| Winchester 760 | Hornady InterLock | 180 grain | 58.0 gr | 64.0 gr | 2,930 fps | Hodgdon |
| Hodgdon H4831SC | Nosler Partition | 200 grain | 59.0 gr | 63.5 gr | 2,750 fps | Hodgdon |
Hodgdon H4350 and IMR 4350 have long been considered the industry standards for the 300 WSM, particularly when loading 165-grain and 180-grain bullets. For heavier 200+ grain bullets, slower powders like H4831SC or Retumbo become more efficient.
300 WSM Bullet And Powder Combinations
The exact component combinations determine the safety and reliability of 300 WSM reloading data.
- Primer choice: The 300 WSM case holds roughly 60 to 70 grains of powder in a wide column. Therefore, Large Rifle Magnum primers are strictly required to ensure complete, consistent ignition, particularly when utilizing slow-burning spherical powders like Winchester 760 or in cold hunting environments.
- Case capacity and seating depth: Because the cartridge is designed for short-action receivers, the 2.860-inch COL is a hard limit for magazine feeding. Seating heavy, long-ogive bullets (like the 212-grain ELD-X) within this limit pushes the base of the bullet deep past the case neck. This reduces internal case capacity and aggressively spikes chamber pressure compared to lighter bullets.
- Brass flow and sizing: The sharp 35-degree shoulder prevents excessive brass flow, extending case life. However, handloaders must ensure they properly bump the shoulder back during full-length resizing to guarantee reliable chambering in tight-tolerance bolt actions.
300 WSM Velocity From Published Data
Published 300 WSM velocity figures depend entirely on the barrel length and bullet weight utilized by the laboratory.
| Bullet | Bullet Weight | Powder | Published Load | Muzzle Velocity | Barrel Length | Firearm | Source |
| Hornady SST | 150 grain | Varget | 59.5 gr (Max) | 3,248 fps | 24.00″ | Universal Receiver | Hodgdon |
| Sierra SBT | 180 grain | H4350 | 63.5 gr (Max) | 2,950 fps | 24.00″ | Universal Receiver | Hodgdon |
| Nosler Partition | 200 grain | H4831SC | 63.5 gr (Max) | 2,750 fps | 24.00″ | Universal Receiver | Hodgdon |
It is crucial to distinguish between manufacturer-published velocity (tested in environmentally controlled laboratories with 24-inch barrels) and independent chronograph testing in the field.
300 WSM Reloading Data By Barrel Length
Barrel length heavily dictates the velocity a reloader will achieve. Major reloading publishers universally utilize 24-inch test barrels to establish their baseline 300 WSM data.
While the 300 WSM is more efficient than the full-length .300 Winchester Magnum due to its shorter powder column, it still requires a sufficiently long barrel to burn magnum powder charges. If a handloader fires a 180-grain load (yielding 2,950 fps from a 24-inch barrel) out of a specialized 22-inch mountain rifle, the velocity will typically drop by 40 to 60 fps. Reloaders must clearly identify their test firearm and barrel length when verifying ballistic trajectories.
300 WSM Energy And Ballistics
The 300 WSM delivers devastating kinetic energy, effectively replicating the ballistics of the .300 Winchester Magnum in a lighter, shorter rifle. Using verified Hodgdon data equivalents from a 24-inch barrel:
- 150-grain SST (at 3,240 fps):
- Muzzle energy: ~3,496 ft-lbs
- Provides incredibly flat trajectories, dropping minimally out to 300 yards.
- 180-grain SBT (at 2,950 fps):
- Muzzle energy: ~3,477 ft-lbs
- Maintains over 2,000 ft-lbs of kinetic energy well past 400 yards, providing massive stopping power for elk and moose.
Manufacturer Data vs Independent Testing
When researching a 300 WSM load data chart, handloaders will encounter:
- Manufacturer-published reloading data: Officially pressure-tested in a laboratory using piezo-electric sensors to guarantee loads stay safely under the 65,000 PSI limit.
- Independent chronograph testing: Velocities recorded by hunters using commercial chronographs over real production rifles. This verifies speed but cannot measure internal chamber pressure.
- User-submitted load reports: Internet forum recipes that often ignore COL variations or push past maximum safe pressures to chase velocity.
Independently measured results frequently differ from published data because consumer rifles feature varying chamber throat tolerances, differing barrel twist rates, and different interior bore friction. Priority must always remain with official, pressure-tested manufacturer data.
300 WSM Pressure And Safety
Safety is paramount when using 300 WSM reloading data. The cartridge operates at a maximum average pressure of 65,000 PSI.
At these high pressures, signs of overpressure can manifest rapidly. Handloaders must vigilantly inspect fired brass for flattened primers, ejector swipe marks on the case head, or stiff bolt lift. Because the 300 WSM utilizes large amounts of powder, changing primer brands or jumping to a brass case with thicker walls (which reduces internal volume) can dramatically spike pressure. Reloaders must drop their powder charges by 10% and work back up anytime a single component is changed.
Furthermore, the 300 WSM features a rebated rim. The cartridge case body is wider than the rim, meaning it feeds slightly differently than traditional belted magnums. Ammunition must be sized perfectly to ensure reliable extraction under maximum pressure.
Best Sources For 300 WSM Reloading Data
The strongest and most authoritative sources for safe 300 WSM load development include:
- Hodgdon Reloading Data Center: Provides extensive, free, pressure-tested online data utilizing Hodgdon, IMR, and Winchester powders (specifically highlighting the exceptional performance of H4350 and IMR 4350).
- Hornady Handbook of Cartridge Reloading: Offers comprehensive component specificity for their InterLock, SST, ELD-X, and ELD Match projectiles.
- Nosler Reloading Guide: An excellent source for high-end hunting projectiles, offering highly detailed data for their Partition, AccuBond, and Ballistic Tip bullets.
- Sierra Reloading Manual: Provides robust baseline data across their GameKing and MatchKing bullet lines utilizing a 24-inch test barrel.
Common 300 WSM Reloading Data Questions
Where can I find 300 WSM reloading data?
Authoritative data is published directly by Hodgdon, Hornady, Nosler, and Sierra in their respective modern manuals and online data centers.
What powders are used in published 300 WSM data?
Common powders include Hodgdon H4350, IMR 4350, Alliant Reloder 17, Reloder 19, Winchester 760, and Hodgdon H4831SC.
What bullet weights have 300 WSM reloading data?
Published data covers lightweight 150-grain hunting projectiles up to heavy 210-grain and 212-grain high-BC match bullets.
What is the best source for 300 WSM reloading data Hodgdon?
The official Hodgdon Reloading Data Center provides the most up-to-date and rigorously pressure-tested data for all Hodgdon, IMR, and Winchester brand powders.
Why does 300 WSM reloading data vary between sources?
Variations occur due to differences in bullet profile, solid copper versus lead-core bearing surfaces, differing laboratory chamber throat tolerances, and varying lots of magnum powder.
Does barrel length affect 300 WSM velocity?
Yes. A 24-inch laboratory test barrel will consistently yield higher velocities than a 22-inch mountain rifle barrel using the exact same load.
Can the same powder charge be used with a different bullet?
No. Different bullet profiles, materials, and bearing surfaces alter internal case capacity and friction, which dramatically changes chamber pressures.
What is the difference between starting and maximum published load data?
The starting load is the safe baseline for working up a new recipe. The maximum load is the absolute highest pressure limit established safely by a ballistic laboratory.
Where can I find pressure-tested 300 WSM data?
Pressure-tested data is available directly from major bullet and powder manufacturers, including Hodgdon, Hornady, and Sierra.
Does Hodgdon publish 300 WSM reloading data?
Yes. Hodgdon provides extensive data specifically developed for the cartridge, heavily emphasizing their Extreme line of powders like H4350.
Does Hornady publish 300 WSM reloading data?
Yes. Hornady publishes incredibly comprehensive load recipes tailored specifically for their .308-inch projectiles, including their renowned ELD-X and SST lines.
Does Nosler publish 300 WSM reloading data?
Yes. Nosler publishes detailed load data for their Partition, AccuBond, and E-Tip bullets in their official reloading manual.