Traditional sporting bullets
Flat-nose, round-nose, and soft-point designs remain important in these cartridge families. For tubular magazines, use ammunition specifically approved by the manufacturer.
THE CARTRIDGE LIBRARY · LARGE-BORE CENTERFIRE
.458 SOCOM
A compact, large-bore centerfire cartridge using .458-class bullets. Factory offerings can include light supersonic and heavier subsonic designs.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Overall length · max
- 2.250 in
57.150 mm - Case length · max
- 1.5799 in
40.130 mm - Bullet maximum
- 0.4579 in
11.630 mm - Rim diameter · max
- 0.4728 in
12.010 mm
Know the exact name
At a glance
- Cartridge family
- Large-bore centerfire
- Bullet specification
- 0.4579 in / 11.630 mmBullet maximum
- Factory examples
- 3 loadsSelected, sourced examples below
- Weight in cited examples
- 250–302 grGrains measure mass, not powder charge
.458 SOCOM is identified by its complete cartridge designation. The resource-table alternative is 458 SOCOM. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
The SOCOM name does not establish a particular factory load's military adoption. It is separate from .450 Bushmaster and .458 Winchester Magnum.
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
Marty ter Weeme of Teppo Jutsu designed the .458 SOCOM as a large-bore cartridge for the compact AR-15 platform. The concept pursued a very different result from the platform’s original small-caliber, high-velocity role: a substantially larger bullet and useful performance from relatively short barrels.
The cartridge was intended to deliver a performance class closer to lighter .45-70 sporting loads while retaining the general size of an AR-15. Its wide range of projectile weights subsequently made it relevant to both supersonic and subsonic ammunition, and civilian hunting became an important part of its identity. The SOCOM name reflects the special-operations-oriented concept behind the project, but the cartridge’s documented designer and commercial development are more informative than the implication of the name alone. It belongs to the broader history of private designers adapting a familiar rifle platform to a markedly different sporting and specialized role.
Historical sources: Sierra: .458 SOCOM cartridge history ↗
Construction changes the story
Loads, variations & specialty offerings
Purpose-built modern loads
Flexible tips, bonded bullets, monolithic expanding bullets, and solids have different functions. A similar exterior shape or shared diameter does not establish equivalent behavior.
Firearm-specific ammunition
Some older cartridge families span firearms with very different operating limits. Keep any product restrictions with the ammunition record and use only loads authorized for that firearm.
In the cited .458 SOCOM examples, bullet weights are 250, 300, 302 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
250 grains
1,900 fps
Lehigh Xtreme Defense
300 grains
1,840 fps
Lehigh Controlled Fracturing
302 grains
1,840 fps
Lehigh Xtreme Penetrator
Compare all 3 cited factory load records
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| SBRSee catalog edition 20 | 302 gr 19.57 g | Lehigh Xtreme Penetrator | 1,840 fps 561 m/s | Not stated here; see source | SBR · PDF p. 13 ↗ |
| SBRSee catalog edition 20 | 250 gr 16.20 g | Lehigh Xtreme Defense | 1,900 fps 579 m/s | Not stated here; see source | SBR · PDF p. 13 ↗ |
| SBRSee catalog edition 20 | 300 gr 19.44 g | Lehigh Controlled Fracturing | 1,840 fps 561 m/s | Not stated here; see source | SBR · PDF p. 13 ↗ |
Explore the published data
Ballistics you can inspect
What can be plotted reliably?
The sources checked for this guide do not provide a comparable barrel-length series. A single factory muzzle-velocity specification does not establish a velocity curve. The factory records and any missing test conditions are identified below.
An estimate needs an anchor and a defensible method. No curve has been invented from bullet diameter or from another cartridge’s name.
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 .458 SOCOM?
A compact, large-bore centerfire cartridge using .458-class bullets. Factory offerings can include light supersonic and heavier subsonic designs.
What diameter does .458 SOCOM use?
The cited dimensional standard lists 0.4579 inches (11.630 mm), bullet maximum. This drawing convention is different from a casual caliber nickname.
Are similarly named cartridges interchangeable?
The SOCOM name does not establish a particular factory load's military adoption. It is separate from .450 Bushmaster and .458 Winchester Magnum.
Are the graph values measured or estimated?
This guide has no supported multi-point graph in the sources reviewed. Its factory specifications and source links are shown in the load section.
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.
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.