Put a .45 caliber bullet in an AR-15 and you get the 458 SOCOM. It turns a familiar rifle into a short-range thumper for hogs, deer and bear. It also makes a quiet, heavy subsonic round for suppressed guns. This guide covers 458 SOCOM ballistics for every load we carry, split into supersonic and subsonic groups. We also cover what the numbers mean in the field.
What Was the 458 SOCOM Designed For?
The 458 SOCOM was developed around 2000. The goal was more stopping power from the AR-15 platform at close range. Its designers wanted heavy bullets without moving to a larger, heavier rifle.
What caliber is it? It fires a .458 inch bullet, the same diameter used in the 45-70 and other big-bore rifles. That gives you a wide range of bullet weights, from 250 grains up past 500.
Is it an AR-15 or AR-10 round? It is built for the AR-15 size lower. You need a dedicated 458 SOCOM upper with the right barrel and bolt. Many standard AR-15 magazines will feed it, but they hold fewer rounds. Check your upper maker’s advice on mags.
Supersonic 458 SOCOM Ballistics
These are the full-speed loads for hunting, defense and the range. They run from 250 to 405 grains.
| Load | Grain | Bullet | Velocity (fps) | Energy (ft-lb) | Pack |
|---|---|---|---|---|---|
| Underwood Xtreme Defense | 250 | Fluted copper | 2,000 | 2,220 | 20-round box |
| SBR | 250 | Barnes TSX | 1,945 | 2,100 | 20-round box |
| Underwood XTP | 300 | JHP | 1,900 | 2,405 | 20-round box |
| Buffalo Bore Ballistic Tip | 300 | Polymer tip | 1,900 | 2,404 | 20-round box |
| Fort Scott TUI | 300 | Solid copper | 1,905 | 2,417 | 20-round box |
| SBR InterLock | 300 | JHP | 1,845 | 2,267 | 20-round box |
| Underwood Xtreme Penetrator | 302 | Fluted copper | 1,840 | 2,255 | 20-round box |
| SBR | 350 | Soft point | 1,750 | 2,380 | 20-round box |
| Buffalo Bore | 350 | Jacketed flat nose | 1,710 | 2,272 | 20-round box |
| Underwood | 350 | FMJ flat nose | 1,650 | 2,116 | 20-round box |
| Buffalo Bore | 400 | Jacketed flat nose | 1,550 | 2,134 | 20-round box |
| Buffalo Bore | 405 | Hard cast | 1,675 | 2,523 | 20-round box |
The fastest here is Underwood Xtreme Defense 250 grain at 2,000 fps. The most energy comes from Buffalo Bore 405 grain hard cast at 2,523 ft-lb. Most 300-grain loads sit near 1,900 fps, like Underwood 300 grain XTP.
Is 458 SOCOM Subsonic?
Most loads are not. But the cartridge is a great fit for subsonic use. A heavy bullet below the speed of sound still carries real weight. Paired with a suppressor, it is quiet and hard-hitting.
| Load | Grain | Bullet | Velocity (fps) | Energy (ft-lb) | Pack |
|---|---|---|---|---|---|
| SBR Subsonic | 450 | FMJ | 1,000 | 999 | 20-round box |
| Buffalo Bore Subsonic | 500 | Hard cast gas check | 1,070 | 1,271 | 20-round box |
| Underwood Subsonic | 500 | Hard cast | 1,075 | 1,283 | 20-round box |
| Buffalo Bore Subsonic | 500 | Jacketed flat nose | 1,075 | 1,283 | 20-round box |
| Grizzly Sub-Sonic | 550 | FMJ | 1,050 | 1,346 | 20-round box |
Grizzly Sub-Sonic 550 grain FMJ lists 1,050 fps and 1,346 ft-lb. Subsonic loads may not cycle every gas system. Test them in your rifle, and check whether your setup needs a different buffer or gas setting.
Reading the Numbers
Velocity is how fast the bullet leaves the muzzle, in feet per second. Energy is in foot-pounds. Energy comes from weight and the square of speed. So the light, fast loads and the heavy, slower loads can post similar energy.
With fat bullets like these, look past energy. A wide, heavy bullet does its work through size and depth. Bullet build tells you how it will behave:
- Hollow points and soft points open up fast. Good for deer and hogs.
- Solid copper bullets, like the Fort Scott TUI 300 grain, hold their weight and are lead-free.
- Hard cast flat nose bullets push deep with little shape change. Good for bears and big hogs.
- FMJ loads are for the range or for subsonic plinking.
What Is 458 SOCOM Good For?
Deer: 300-grain expanding bullets are a sound pick. Keep shots close; these blunt bullets shed speed quickly.
Hogs: a 300 to 350-grain bullet with good weight retention. Hogs have tough shoulders.
Bear defense: 400-grain jacketed or 405-grain hard cast loads.
Suppressed shooting: 450 to 550-grain subsonic loads.
Some states limit deer hunting to straight-walled cartridges. Rules differ on which rounds qualify, so check your state’s regulations before you hunt.
Barrel Length and Conditions
Fort Scott and Buffalo Bore both list a 16-inch test barrel for some of their loads. That matches many 458 SOCOM uppers. Shorter barrels will lose some speed. Very cold weather can slow some powders. Altitude has little effect on muzzle speed, but thin air helps the bullet hold speed downrange. Treat the 458 SOCOM ballistics in these tables as a starting point and chronograph your own rifle.
Weighing your options? Compare the 450 Bushmaster ballistic data guide, the other big-bore AR round. Or see the 45-70 Government ballistic data guide for the classic lever-gun round with the same bullet size.
Shop 458 SOCOM Ammo
Find every load above in our 458 SOCOM ammo collection. Reloaders can also pick up Starline 458 SOCOM brass.
Frequently Asked Questions
What is 458 SOCOM good for?
The 458 SOCOM suits deer, hogs and black bear at close to moderate range. It also works well as a suppressed subsonic round with heavy bullets. It gives an AR-15 size rifle big-bore power. Check your state’s hunting rules before you take it afield.
Does 458 SOCOM use 5.56 magazines?
Many standard AR-15 magazines will feed 458 SOCOM, but they hold far fewer rounds because the cartridge is so wide. Some shooters change the follower for better feeding. Check your upper maker’s advice on which magazines work best.
Is 458 SOCOM an AR-15 or AR-10?
It is built for an AR-15 size lower receiver. You swap in a dedicated 458 SOCOM upper with the right barrel and bolt. You do not need an AR-10 frame to shoot it.
Is 458 SOCOM subsonic?
Most loads are supersonic. Some are made to be subsonic for use with a suppressor. In our stock, SBR 450 grain subsonic FMJ lists 1,000 fps and Grizzly Sub-Sonic 550 grain lists 1,050 fps. Test subsonic loads for reliable cycling.
What caliber is 458 SOCOM?
It fires a .458 inch bullet. That is the same bullet diameter used by the 45-70 Government. The case is short and wide so it fits in an AR-15 size magazine well.
