SBR 458 Socom Ammo 300 Grain Barnes Triple-Shock X Solid Hollow Point Lead Free Box of 20

Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.

For medium-game hunters running AR-15 platforms in 458 Socom, the SBR 300-grain Barnes Triple-Shock X load bridges power and penetration in a lead-free package. Driven to 1840 feet per second from a 16-inch barrel, this all-copper hollow point sheds zero weight on impact — four razor-edged petals open while the shank pushes through shoulder blades, ribs, and heavy tissue. SBR Ammunition was among the first manufacturers to chamber 458 Socom commercially, and this 300-grain TSX load reflects that lineage: G1 ballistic coefficient of 0.234, sectional density of 0.204, and supersonic flight to typical hunting ranges. You seat 20 boxer-primed brass cases that reload cleanly and hold zero corrosive residue.

Built for the Box

Barnes machines each 300-grain Triple-Shock X projectile from solid copper rod stock, eliminating lead from both core and jacket. The hollow-point cavity meters expansion: as hydraulic pressure floods the nose, four pre-scored cuts peel back into cutting petals while the copper shank remains intact. This design typically retains 100 percent of the original 300 grains, channeling all kinetic energy into wound cavity rather than fragmentation. SBR seats these bullets to 458 Socom SAAMI spec, headspacing on the case mouth for reliable magazine feeding in AR lowers adapted to the straight-wall cartridge. Boxer primers and new brass cases mean you reload after the hunt, and the non-corrosive priming mixture keeps bores and chambers clean through wet-weather sits.

Load Profile

This load serves hog hunters, whitetail stalkers, and predator callers working inside 200 yards — ranges where the 458 Socom’s arc remains flat and energy stays above 1500 ft-lbs. The all-copper construction satisfies lead-free hunting zones in California and other jurisdictions, and the four-petal expansion mimics controlled-expansion bonded bullets without the jacket-separation risk. Browse the full 458 Socom ammo catalog for practice ball and barrier-blind defensive loads to complement this hunting round.

Who It’s For

You’re running a 458 Socom upper on an AR-15 lower for close-range hunting — timber stands for deer, early-morning ambush for hogs, or thick-brush predator work where shots land inside 150 yards. You need a bullet that punches through shoulder bone without shedding jacket material, and you hunt in lead-restricted areas or prefer monolithic projectiles for their penetration advantage. The 300-grain TSX pairs terminal performance with reloadable brass, making it a sustainable choice for hunters who cast their own loads or stockpile components. If you chase dangerous game at extended range or need barrier penetration for defensive use, consider heavier subsonic loads or bonded soft-points; this load maximizes wounding in soft tissue and bone, not hardcover or long-distance trajectory.