Sourcing accurate .300 WSM load data is crucial for unlocking the magnum-level performance of this highly efficient short-action cartridge.
This guide compiles comprehensive .300 WSM reloading data to help you safely develop the perfect hard-hitting round for your mountain rifle or precision setup.
Whether you are loading lightweight 150-grain projectiles for deer or heavy 200-grain bullets for elk, always cross-reference these published figures before charging your cases.
.300 WSM Load Data
| Bullet | Bullet Weight | Powder | Published Starting Load | Published Maximum Load | Published Velocity | Barrel Length / Firearm | Source |
| Hornady SST | 150 gr | Varget | 55.0 gr | 59.5 gr (63,000 PSI) | 3,050 – 3,250 fps | 24″ / Universal Receiver | Hodgdon |
| Nosler Partition | 165 gr | H4350 | 60.5 gr | 64.5 gr (64,000 PSI) | 2,950 – 3,150 fps | 24″ / Universal Receiver | Hodgdon |
| Sierra GameKing | 180 gr | IMR 4350 | 59.0 gr | 63.5 gr | 2,850 – 3,020 fps | 24″ / Universal Receiver | Sierra Bullets |
| Barnes TTSX | 180 gr | H4831SC | 62.0 gr | 66.5C gr (63,800 PSI) | 2,800 – 2,980 fps | 24″ / Universal Receiver | Hodgdon |
| Hornady ELD-X | 200 gr | Reloder 22 | 58.5 gr | 62.8 gr | 2,650 – 2,820 fps | 24″ / Universal Receiver | Alliant Powder |
.300 WSM Reloading Data
| Bullet | Bullet Weight | Powder | Published Starting Load | Published Maximum Load | Published Velocity | Barrel Length / Firearm | Source |
| Barnes LRX | 145 gr | Superformance | 66.0 gr | 70.5 gr (64,200 PSI) | 3,150 – 3,350 fps | 24″ / Universal Receiver | Hodgdon |
| Hornady InterLock | 150 gr | W760 | 62.0 gr | 66.5 gr (63,500 PSI) | 3,080 – 3,280 fps | 24″ / Universal Receiver | Hodgdon |
| Nosler AccuBond | 165 gr | IMR 4831 | 61.0 gr | 65.5C gr | 2,950 – 3,120 fps | 24″ / Universal Receiver | Nosler |
| Sierra MatchKing | 175 gr | Reloder 17 | 60.0 gr | 64.5 gr | 2,900 – 3,100 fps | 24″ / Universal Receiver | Alliant Powder |
| Berger Hybrid Target | 210 gr | H1000 | 61.5 gr | 65.5C gr (64,500 PSI) | 2,600 – 2,750 fps | 24″ / Universal Receiver | Hodgdon |
Understanding the .300 WSM Reloading Data
Reading .300 WSM reloading data requires an understanding of the cartridge’s unique short, fat case geometry. Introduced in 2001, the .300 Winchester Short Magnum was designed to duplicate the legendary ballistics of the standard .300 Winchester Magnum while fitting perfectly into a lighter, stiffer short-action rifle. The tables above provide safe baselines using modern powders that efficiently utilize the cartridge’s 35-degree shoulder and wide powder column. Pay close attention to compressed loads (denoted with a “C”), which are very common when seating long, heavy bullets deeply into the short casing.
.300 WSM Bullet Weight Reloading Data
The .300 WSM dominates with a wide spectrum of .30-caliber (.308 diameter) bullets, with weights typically ranging from 150 grains up to 210 grains. Lightweight 150-grain projectiles are excellent for achieving laser-flat trajectories on medium game like deer and antelope. However, the cartridge truly shines when loaded with premium 165-grain, 180-grain, and 200-grain bullets. These mid-to-heavyweight projectiles offer exceptional ballistic coefficients and the deep penetration required for hunting large North American game.
.300 WSM Powder Reloading Data
Powder selection for the .300 WSM relies heavily on medium-slow to slow-burning rifle propellants that thrive in short, wide powder columns. Extruded powders like H4350, IMR 4350, and Reloder 17 are historically considered the absolute best choices for the cartridge, consistently delivering maximum velocities with 165-grain and 180-grain bullets. When pushing heavier 200-grain or 210-grain projectiles, slower powders such as H4831SC, Reloder 22, and H1000 provide a smoother pressure curve and prevent dangerous early pressure spikes.
.300 WSM Bullet and Powder Combinations
Pairing the right bullet with the appropriate powder is critical for achieving magnum velocities without exceeding safe chamber pressures. A 165-grain hunting bullet paired with a healthy charge of H4350 or IMR 4350 is a legendary combination that balances extreme speed, temperature stability, and pinpoint accuracy. If you are loading heavy 200-grain monolithic or match bullets, dropping down to a slower powder like Reloder 22 or H1000 ensures you can safely maximize your powder charge without compressing the load too aggressively.
.300 WSM Velocity From Published Data
Published velocity figures for the .300 WSM prove that it comfortably runs shoulder-to-shoulder with the traditional .300 Winchester Magnum. With 150-grain bullets, reloaders can easily break the 3,250 fps mark out of a standard test barrel. More importantly, the cartridge can drive a heavily constructed 180-grain bullet to nearly 3,000 fps. This extreme velocity guarantees reliable expansion and massive energy transfer on large game targets at extended ranges.
.300 WSM Reloading Data by Barrel Length
Most published load data for the .300 WSM utilizes a 24-inch laboratory test barrel to simulate the standard barrel length of most magnum sporter rifles. Because the cartridge relies on slower-burning powders, running it in a shorter 22-inch or 20-inch mountain rifle barrel will result in a noticeable velocity loss of approximately 30 to 45 fps per inch of reduced barrel length. The powder charge should not be increased to chase 24-inch velocities, as this will lead to dangerous overpressure.
.300 WSM Energy and Ballistics
The .300 WSM delivers devastating kinetic energy, routinely generating over 3,500 foot-pounds of energy at the muzzle. The short, fat powder column provides highly consistent ignition, often resulting in lower extreme velocity spreads and exceptional long-range precision. The trajectory remains remarkably flat out to 400 yards, and the high-BC .30-caliber bullets easily buck the wind, making it an extraordinarily forgiving cartridge for cross-canyon hunting scenarios.
.300 WSM Hunting Applications
The .300 WSM is a premier, do-it-all big game cartridge that excels in steep, mountainous terrain where lightweight, short-action rifles are preferred. Loaded with heavily constructed 180-grain or 200-grain bullets like the Barnes TTSX, Nosler Partition, or Hornady ELD-X, it provides the necessary penetration and hydrostatic shock to cleanly harvest elk, moose, caribou, and large bears. When loaded with 150-grain expanding bullets, it is equally devastating on whitetail and mule deer.
Manufacturer Data vs. Independent Testing
Because the .300 WSM operates at high pressures within a wide case body, it generates significant bolt thrust. Relying strictly on official manufacturer data is paramount for safety. Independent forum testing frequently features “hot loads” that ignore the signs of brass flow or tight bolt lift in an attempt to beat traditional .300 Win Mag velocities. Always use verified manufacturer load data to establish a safe baseline and prevent catastrophic failure or premature wear on your rifle’s locking lugs.
.300 WSM Pressure and Safety
The SAAMI Maximum Average Pressure (MAP) for the .300 WSM is set at a stout 65,000 PSI. Because the cartridge features a very sharp 35-degree shoulder and a relatively short neck, reloaders must pay close attention to bullet seating depth and neck tension. Seating long bullets deeply into the powder column reduces internal case capacity and drastically spikes pressures. Always monitor your fired brass for flattened primers, ejector marks, or heavy bolt lift, and always start at the published minimum charge.
Best Sources for .300 WSM Reloading Data
The most reliable sources for load data are the printed manuals and digital databases provided by legacy component manufacturers. The Hodgdon Reloading Data Center offers incredibly comprehensive, free digital tables for their premier extruded and spherical powders. Additionally, the Hornady Handbook of Cartridge Reloading and the Nosler Reloading Guide provide safe, meticulously vetted recipes specifically tailored to their popular hunting and match projectiles.
Frequently Asked Questions
Where can I find .300 WSM reloading data?
You can find accurate .300 WSM reloading data in published manuals from Hornady, Nosler, and Sierra, or digitally on the official Hodgdon Reloading Data Center website.
What powders are listed in published .300 WSM data?
Commonly listed powders include medium-slow to slow-burning propellants such as H4350, IMR 4350, Reloder 17, W760, H4831SC, Reloder 22, and H1000.
What bullet weights are covered in these tables?
These tables primarily cover the optimal .30-caliber bullet weights for the cartridge, ranging from 145-grain monolithic projectiles up to heavy 210-grain long-range match bullets.
Does barrel length affect .300 WSM velocity?
Yes, shooting from a 22-inch mountain rifle barrel rather than a standard 24-inch test barrel will typically result in a velocity loss of approximately 30 to 45 feet per second per inch.
Can I use standard rifle primers for .300 WSM?
No, manufacturer data almost universally dictates the use of Large Rifle Magnum primers to ensure the reliable ignition of the heavy charges of slow-burning powder.
What is the difference between .300 WSM load data and reloading data?
There is no practical difference; both terms refer to the precise recipes of powder charges, bullet weights, and primers required to safely assemble the cartridge.
Why do published velocity figures differ between sources?
Velocity figures differ because testing facilities use varying specific test barrels, environmental conditions, brass lot capacities, and primer types during their distinct testing protocols.
Should I use the maximum published load?
You should never start with the maximum published load; always begin with the minimum recommended starting charge and carefully work up while monitoring your brass for pressure signs.
Can I use data from one bullet manufacturer for another bullet?
You should only use data specifically designed for the exact bullet you are loading, as variations in bullet bearing surface length and overall profile drastically alter internal case capacity and chamber pressure.
Where should I verify .300 WSM load data before reloading?
You should strictly verify all load data against an official, recently published manufacturer manual or a powder company’s official online database before assembling any ammunition.