The 458 SOCOM – Big Bore AR Calibers Part I

The AR 15 puts them in modular. As a platform, the rifle can be converted to basically any use. It can be a carbine, DMR rifle, light sniper rifle, and an SMG-sized silent killer. It’s been adopted to numerous calibers, including big-bore calibers. Today we are looking at one of the more popular AR big-bore calibers, the .458 SOCOM.

History of the .458 SOCOM

The .458 SOCOM carries the name SOCOM, but it should be noted the round was never used by any American military force. However, development began based on discussions with operators that had participated in Operation Gothic Serpent, aka Blackhawk Down. The operators complained that it took several 5.56 rounds to kill the enemy.

This brought forth the idea of a heavy-hitting rifle caliber that would deliver a big heavy round and shut down an opponent quickly. The round would be devastating to the body and transmit a hefty amount of energy to the enemy.

Marty ter Weeme of Teppo Jutsu LLC developed the round in 2000. In early 2001 Troy Rumore’s rifle company Tromix designed the first .458 SOCOM rifle.

The idea behind the round was simple: Make it big, make it powerful, and make it hard-hitting. Also, it needs to work inside the AR platform. Specifically, the M4, that was the bell of the special operations ball in 2000. Additionally, the big heavy round should be subsonic to allow for the effective use of suppressors.

The .458 caliber was chosen because the market already had a rather large selection of .458 projectiles of varying weights. Rumore suggested using a lengthened .50AE case for reliability issues. The case was lengthened and necked down to accept the .458 projectile.

The end result was a hard-hitting and huge projectile that worked in the standard M4 lower receiver. A standard bugger, buffer spring, STANAG magazines, and magazine well could be used with the .458 SOCOM. In theory, all a soldier needed to do was replace the 5.56 upper with a .458 upper, and they’d be good to go.

The .458 SOCOM in Real Life

SOCOM never adopted the round, and it admittedly didn’t see any known overseas action. However, people like ARs and people like large projectiles. The round proved popular among civilian shooters and even hunters looking for a close-range, animal-stopping round.

The .458 SOCOM is a powerful round with a big fat projectile and a rather short case. As you’d imagine, the caliber isn’t made for long-range performance. Different projectile weights will change the range of the gun. A big 600-grain projectile won’t go as fast or as far as a lighter 250-grain cartridge. Regardless, this is a short-range round.

It was envisioned to be a fight stopping round for close-range fights in urban environments like Mogadishu and later the caves of Afghanistan. The round’s max range is about 150 yards. Anything further than that, and those big pills lose velocity and start dropping exceptionally fast.

It’s easy to expect recoil to be harsh and brutal, but in reality, it’s not so bad. The heftier subsonic rounds and the lighter 250- to 300-grain rounds aren’t bad at all. In my experience, the mid-weight rounds are the worst, and I’d compare the recoil to that of a 20-gauge shotgun.

In an M4 platform, a shooter can dispatch rapid follow-up shots with ease. Engaging multiple targets or firing fast follow-up shots isn’t hard.

The .458 SOCOM accomplishes its task of hitting hard and penetrates quite deep through soft targets. Hunters wield the round against dangerous game, and one-shot drops are the norm. Hunting massive hogs, bears, and elk are commonplace, and the gun does well against those big beasts. It’s a rock-solid brush hunting round.

The Guns

The AR 15 is the most common platform to find the .458 SOCOM chambered in. Plenty of companies produce upper receivers and complete guns in the .458 SOCOM. With standard 30 round, 5.56 magazines, shooters can tote 10 rounds of .458 SOCOM.

Outside of AR 15s, the .458 SOCOM found its way into bolt-action rifles produced by custom shops like Mars Armory. The round drifted into lever guns and single shots, as well.

While the .458 SOCOM never saw action, it’s proven to be a very capable big-bore AR 15 caliber and does extremely well in its niche. When you need to stop a hogzilla, the .458 is a hammer that’s up to the task.