The .458 SOCOM (11.5x40mm RB) is a large-caliber cartridge with a .458-inch bullet diameter, developed in 2000 by Marty ter Weeme of Teppo Jutsu for the AR-15/M4 platform and used for hunting medium and large game as well as defensive and law-enforcement roles.
The 458 SOCOM is not listed in SAAMI’s rifle (Z299.4), handgun (Z299.3) or rimfire (Z299.1) standards, so there is no SAAMI reference velocity, pressure limit or test barrel to quote for it. This guide charts what the makers of the loads we stock publish for them instead, and compares the 458 SOCOM with the 450 Bushmaster, which SAAMI does standardise.
458 SOCOM ballistics chart: manufacturer-published loads
These are the manufacturers’ own figures for specific loads we stock, taken from each maker’s page for the item number shown. There is no SAAMI reference for this cartridge, and each maker chose its own test barrel, so the figures should not be laid directly beside another brand’s.
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| Load | Item no. | Bullet weight | Bullet | Muzzle velocity | Muzzle energy | Ballistic coefficient | Test barrel |
|---|---|---|---|---|---|---|---|
| SBR Ammunition TTSX (TIPPED TSX) / TAC-X | SL45827 | 300 gr | TTSX (TIPPED TSX) / TAC-X | 1,840 fps | 2,256 ft-lb | 0.236 G1 | Not published |
| Underwood Ballistic Tip® Hunting | 415 | 300 gr | Ballistic Tip® Hunting | 1,900 fps | 2,405 ft-lb | 0.25 G1 | Not published |
| Underwood Full Metal Jacket-Flat Nose | 461 | 350 gr | Full Metal Jacket-Flat Nose | 1,650 fps | 2,116 ft-lb | Not published | Not published |
| Buffalo Bore JFN | 47C | 350 gr | JFN | 1,710 fps | 2,272 ft-lb | Not published | 16-inch |
| Buffalo Bore JFN | 47D | 400 gr | JFN | 1,550 fps | 2,134 ft-lb | Not published | 16-inch |
| Buffalo Bore Hard Cast, Gas Checked, Flat Nose | 47E | 405 gr | Hard Cast, Gas Checked, Flat Nose | 1,675 fps | 2,523 ft-lb | Not published | 16-inch |
| Buffalo Bore HARD CAST GC FN | 47G | 500 gr | HARD CAST GC FN | 1,115 fps | Not published | Not published | 16-inch |
| Grizzly Cartridge Company Full Metal Jacket Spitzer Subsonic | GC458SCM | 550 gr | Full Metal Jacket Spitzer Subsonic | 1,050 fps | 1,346 ft-lb | Not published | Not published |
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| Load (test barrel) | Muzzle | 50 yd | 75 yd | 100 yd | 150 yd | 200 yd |
|---|---|---|---|---|---|---|
| SBR Ammunition 300 gr (barrel not published) | 1,840 fps / 2,256 ft-lb | 1,691 fps | 1,620 fps | 1,552 fps | 1,424 fps | 1,309 fps |
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| Load (zero) | 50 yd | 75 yd | 100 yd | 150 yd | 200 yd |
|---|---|---|---|---|---|
| SBR Ammunition 300 gr (50 yd zero) | 0 in | −0.37 in | −1.56 in | −6.74 in | −14.39 in |
What the numbers mean for a shot
The 8 loads charted above, from SBR Ammunition, Underwood, Buffalo Bore and Grizzly Cartridge Company, run from 300 to 550 grains, with published muzzle velocities of 1,050 to 1,900 fps and published muzzle energies of 1,346 to 2,523 ft-lb. Each maker fired its load in its own test barrel, so a difference between two brands can come from the barrel as well as the load. Downrange velocity, energy and drop appear only where a maker publishes them, and only out to the last range it publishes.
None of this is SAAMI data. Each product in our 458 SOCOM ammo range lists whatever its maker publishes for that item.
Chamber and pressure
This page states no SAAMI pressure limit for the 458 SOCOM. Fire 458 SOCOM ammunition only in a firearm chambered for it, and follow both the ammunition maker’s and the firearm maker’s instructions. Several unrelated cartridges share a number, so match the full designation on the box to the marking on your barrel.
458 SOCOM vs 450 Bushmaster: what the data supports
A like-for-like comparison needs both cartridges measured the same way. SAAMI standardises the 450 Bushmaster, so its figures come from one standard test barrel. The 458 SOCOM has no SAAMI figures, so its numbers come from individual makers and their own barrels. The table sets them side by side with the source of each figure stated, and should be read that way.
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| Specification | 458 SOCOM | 450 Bushmaster |
|---|---|---|
| Listed by SAAMI | No | Yes |
| Maximum average pressure | Not published by SAAMI | 38,500 psi (SAAMI) |
| Bullet weights | 300 to 550 gr (loads we stock) | 250 to 395 gr (SAAMI reference loads) |
| Muzzle velocity | 1,050–1,900 fps (manufacturer-published, each in its own barrel) | 1,050–2,250 fps (SAAMI reference, 24.000 in test barrel) |
| Muzzle energy | 1,346–2,523 ft-lb (where the maker publishes it) | 967–2,810 ft-lb (computed from SAAMI velocity) |
What this cannot settle is which cartridge is more powerful in your rifle: the two columns come from different sources and different barrels. We stock the other side of this comparison too: 450 Bushmaster ammo.
458 SOCOM ballistics questions
Does SAAMI standardise the 458 SOCOM?
No. SAAMI’s rifle, handgun and rimfire standards do not list the 458 SOCOM, so there is no SAAMI maximum pressure, reference velocity or test barrel for it. The figures on this page are the ones each maker publishes for its own loads.
What muzzle velocity do manufacturers publish for the 458 SOCOM?
For the 8 loads we stock from SBR Ammunition, Underwood, Buffalo Bore and Grizzly Cartridge Company, the makers publish muzzle velocities from 1,050 to 1,900 fps, for bullet weights from 300 to 550 grains. Each maker measured its own load in its own test barrel, so these are not reference figures and are not directly comparable between brands.
Is the 458 SOCOM more powerful than the 450 Bushmaster?
The two cannot be compared like for like, because SAAMI publishes reference data for the 450 Bushmaster but not for the 458 SOCOM. The 8 loads charted here for the 458 SOCOM publish muzzle energies of 1,346 to 2,523 ft-lb, each in its maker’s own barrel, against SAAMI reference loads for the 450 Bushmaster that compute to 967 to 2,810 ft-lb from a 24.000 in test barrel.
What is the effective range of the 458 SOCOM?
Effective range is not a published specification for the cartridge; it depends on the bullet, the load and the shooter. Where a maker publishes downrange velocity and energy for a load, the tables above show it, and only out to the last range that maker publishes.
How much does the 458 SOCOM drop?
Where a maker publishes a trajectory, the trajectory table above gives the drop with the zero range stated. A drop figure is unusable without its zero, so use the table for the specific load.
Where to buy these loads
Hilltop Armory carries 458 SOCOM ammunition from Buffalo Bore, SBR Ammunition, Underwood, Grizzly Cartridge Company, Fort Scott Munitions and HSM Ammunition. Browse the full 458 SOCOM ammo range.
