History
Winchester introduced the .300 Winchester Short Magnum in 2001 and kicked off the short-magnum movement. The goal was .300 Winchester Magnum performance from a short action: a fat, beltless case that burned cleanly and fed through a lighter, stiffer rifle. It worked, and the .300 WSM became the most successful of the short magnums by a wide margin.
Hunters who wanted magnum reach in a compact, light rifle took to it quickly, and factory support stayed strong. That short, fat powder column burns consistently, which is partly why the cartridge built a reputation for accuracy on top of performance.
Lineage
The case is the founding member of the Winchester Short Magnum family: short, fat, beltless, with a rebated rim sized to a .535 inch standard magnum bolt face. It headspaces on its shoulder and pushes a .308 inch (7.82mm) bullet. The siblings are the other WSMs, the .270 WSM, 7mm WSM, .325 WSM, and the modern 6.8 Western. The rival is the standard-length .300 Winchester Magnum it was built to match.
Specifications
| Spec | Value |
|---|---|
| Case type | Rimless (rebated), bottlenecked (short magnum) |
| Bullet diameter | 7.82 mm (.308 in) |
| Neck diameter | 8.74 mm (.344 in) |
| Shoulder diameter | 13.67 mm (.538 in) |
| Rim diameter | 14.10 mm (.555 in) |
| Case length | 53.34 mm (2.100 in) |
| Overall length | 72.64 mm (2.860 in) |
| Case capacity | ~80 gr H2O (nominal; varies by brand) |
| Primer size | Large rifle magnum |
| Belted | No |
| Rifling twist | 1 in 10 in (SAAMI standard) |
| Max pressure | 65,000 psi (SAAMI) |
| Recommended barrel | 30 in, 1:10 twist |
Barrel Design
This is an efficient cartridge, not an overbore one. It reaches useful velocity without an extreme barrel, which is why Winchester and most makers chamber it in 24 inch tubes built for compact hunting rifles.
For the long-range mission this site is built around, I'd put my baseline at 30 inches to wring out the last of the velocity and tighten standard deviation for distance work. That runs longer than most factory .300 WSMs. A 24 to 26 inch barrel gives up only modest velocity while making a much handier rifle, so a shorter tube is entirely reasonable for a hunting build.
Twist is 1:10, standard and well matched to the 165 to 200 grain bullets the cartridge usually wears. It stabilizes the heavier 185 and 200 grain match and hunting bullets; the very heaviest .30 caliber match bullets are happier in a longer-throated magnum. The tables below are computed at the 30 inch recommended barrel.
Range Ammo Performance
Federal Fusion · 180 gr Bonded SP $1.05/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 3082 | -0.3 | 3796 | 0.4 |
| 100 | 2892 | 0.0 | 3342 | 0.2 |
| 200 | 2710 | -0.3 | 2934 | 0.4 |
| 300 | 2535 | -0.9 | 2567 | 0.6 |
| 400 | 2366 | -1.5 | 2237 | 0.8 |
| 500 | 2204 | -2.3 | 1941 | 1.0 |
| 600 | 2048 | -3.1 | 1677 | 1.2 |
| 700 | 1899 | -4.1 | 1442 | 1.5 |
| 800 | 1758 | -5.1 | 1235 | 1.8 |
| 900 | 1624 | -6.3 | 1055 | 2.1 |
| 1000 | 1501 | -7.6 | 900 | 2.4 |
| 1100 | 1388 | -9.0 | 769 | 2.8 |
| 1200 | 1287 | -10.7 | 662 | 3.2 |
| 1300 | 1201 | -12.5 | 576 | 3.6 |
| 1400 | 1130 | -14.6 | 510 | 4.0 |
| 1500 | 1073 | -16.9 | 460 | 4.4 |
| 1600 | 1027 | -19.5 | 422 | 4.8 |
| 1700 | 988 | -22.3 | 390 | 5.3 |
| 1800 | 955 | -25.3 | 364 | 5.7 |
| 1900 | 925 | -28.6 | 342 | 6.1 |
| 2000 | 898 | -32.2 | 322 | 6.5 |
| 2100 | 873 | -36.0 | 305 | 6.9 |
| 2200 | 850 | -40.0 | 289 | 7.4 |
| 2300 | 828 | -44.3 | 274 | 7.8 |
| 2400 | 808 | -48.9 | 261 | 8.2 |
| 2500 | 789 | -53.7 | 249 | 8.6 |
| 2600 | 771 | -58.7 | 237 | 9.0 |
| 2700 | 753 | -64.0 | 227 | 9.5 |
| 2800 | 737 | -69.6 | 217 | 9.9 |
| 2900 | 721 | -75.4 | 208 | 10.3 |
| 3000 | 706 | -81.5 | 199 | 10.8 |
| 3100 | 692 | -87.9 | 191 | 11.2 |
| 3200 | 678 | -94.6 | 184 | 11.6 |
| 3300 | 665 | -101.5 | 177 | 12.1 |
| 3400 | 653 | -108.8 | 170 | 12.6 |
Muzzle velocity 3082 fps is estimated at 30 in from the 24 in factory figure of 2950 fps at about 22 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Match Ammo Performance
HSM Trophy Gold · 210 gr Berger VLD Hunting $3.44/rd
| Range (yd) | Velocity (fps) | Elevation (mil) | Energy (ft-lb) | Windage (mil) |
|---|---|---|---|---|
| 0 | 2848 | -0.4 | 3782 | 0.3 |
| 100 | 2711 | 0.0 | 3426 | 0.2 |
| 200 | 2577 | -0.4 | 3095 | 0.3 |
| 300 | 2446 | -1.0 | 2791 | 0.5 |
| 400 | 2320 | -1.8 | 2510 | 0.7 |
| 500 | 2198 | -2.6 | 2252 | 0.9 |
| 600 | 2079 | -3.4 | 2016 | 1.1 |
| 700 | 1964 | -4.4 | 1799 | 1.3 |
| 800 | 1853 | -5.4 | 1600 | 1.5 |
| 900 | 1744 | -6.5 | 1418 | 1.7 |
| 1000 | 1638 | -7.7 | 1251 | 2.0 |
| 1100 | 1535 | -9.1 | 1098 | 2.3 |
| 1200 | 1435 | -10.5 | 960 | 2.5 |
| 1300 | 1338 | -12.1 | 834 | 2.9 |
| 1400 | 1245 | -13.9 | 722 | 3.2 |
| 1500 | 1157 | -15.9 | 624 | 3.6 |
| 1600 | 1091 | -18.0 | 555 | 4.0 |
| 1700 | 1055 | -20.4 | 519 | 4.4 |
| 1800 | 1026 | -23.1 | 491 | 4.8 |
| 1900 | 1000 | -25.9 | 467 | 5.2 |
| 2000 | 977 | -29.0 | 445 | 5.5 |
| 2100 | 955 | -32.2 | 425 | 5.9 |
| 2200 | 934 | -35.7 | 407 | 6.3 |
| 2300 | 914 | -39.3 | 389 | 6.6 |
| 2400 | 895 | -43.2 | 373 | 7.0 |
| 2500 | 876 | -47.2 | 358 | 7.4 |
| 2600 | 858 | -51.4 | 343 | 7.7 |
| 2700 | 841 | -55.8 | 330 | 8.1 |
| 2800 | 824 | -60.4 | 317 | 8.4 |
| 2900 | 808 | -65.2 | 305 | 8.8 |
| 3000 | 793 | -70.2 | 293 | 9.2 |
| 3100 | 778 | -75.4 | 282 | 9.6 |
| 3200 | 763 | -80.8 | 271 | 9.9 |
| 3300 | 749 | -86.5 | 262 | 10.3 |
| 3400 | 736 | -92.3 | 252 | 10.7 |
Muzzle velocity 2848 fps is estimated at 30 in from the 26 in factory figure of 2760 fps at about 22 fps per inch. Expect your own barrel to read a little differently. Velocity is color coded green supersonic, yellow transonic, red subsonic; treat transonic and subsonic rows as approximate.
Trajectory
FAQ
What barrel length and twist should I run?
A 1:10 twist handles the 165 to 200 grain bullets the .300 WSM is built around. For barrel length, 24 inches is the practical factory standard for a compact rifle; the 30 inch baseline I'd choose maximizes velocity for dedicated long-range use.
How does it compare to the .300 Winchester Magnum?
The .300 WSM matches the .300 Win Mag's performance with the heavier short-magnum bullets while fitting a short action, so it can ride in a lighter, stiffer rifle. The .300 Win Mag has a slight edge with the very heaviest bullets and even broader ammunition availability.
Why is it considered accurate?
The short, fat case burns its powder consistently, which tends to produce low velocity spreads, and short actions are inherently stiff. Those traits gave the .300 WSM a strong accuracy reputation from the start.
What is the .300 WSM good for?
Magnum-class hunting from deer to elk in a compact, lightweight rifle, and capable long-range work. Its blend of performance, efficiency, and short-action packaging is why it outlasted the other short magnums.