Last reviewed: 2026-04-19 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
For shooters running 300 AAC Blackout platforms who want a range-focused supersonic load that cycles every time, the Sellier & Bellot 124 grain FMJ delivers consistent muzzle velocity, boxer-primed brass, and a full metal jacket bullet profile that punches paper without fouling suppressors as fast as soft-point hunting rounds. Engineered for high-volume carbine drills, this 20-round box ships at 2165 fps from a 16-inch barrel and carries 1290 foot-pounds of energy at the muzzle — enough to ring steel at 200 yards while keeping your brass reloadable for a second life on the bench.
Performance at a Glance
The 124 grain full metal jacket leaves the muzzle at 2165 fps, posting a G1 ballistic coefficient of 0.292 — enough to maintain supersonic flight well past typical carbine engagement ranges. Sellier & Bellot manufactures this cartridge in boxer-primed, non-corrosive brass cases that feed reliably in AR-15 and bolt-action 300 Blackout rifles. Czech production standards and CBC/Magtech group ownership since 2009 ensure lot-to-lot consistency; each case headstamps with the S&B mark and measures within SAAMI spec for pressure and dimensional tolerances.
Specs at a Glance
| Spec | Value |
|---|---|
| Caliber | 300 AAC Blackout (7.62x35mm) |
| Bullet weight | 124 grains |
| Bullet type | Full Metal Jacket |
| Muzzle velocity | 2165 fps (16″ barrel) |
| Muzzle energy | 1290 ft·lbs |
| Rounds/box | 20 |
| Case | Brass |
| Primer | Boxer |
| Corrosive | No |
| Reloadable | Yes |
| Ballistic coefficient (G1) | 0.292 |
| Velocity rating | Supersonic |
| Intended use | Range & Target |
| Manufacturer | Sellier & Bellot |
The 300 AAC Blackout platform was designed for versatility — subsonic suppressed fire or supersonic barrier penetration from the same magazine. This 124 grain FMJ sits squarely in the supersonic camp, cycling gas systems cleanly and delivering enough downrange energy for defensive training or varmint control out to 300 yards. Compare other loads in our 300 Blackout ammo category to match ballistic performance to your use case.
Safe Handling & Compliance
Federal law requires purchasers to be at least 18 years old for rifle and shotgun ammunition, and at least 21 for handgun ammunition. Ammunition cannot be shipped to certain states, counties, and cities — review our ammunition shipping restrictions before ordering. Store ammunition in a cool, dry location away from heat sources and out of reach of unauthorized users.
- Follow the four rules of firearm safety on every range trip — treat every gun as loaded, keep your finger off the trigger until ready to fire, never point at anything you’re not willing to destroy, and know your target and what’s beyond it.
- Verify current state and local ammunition laws before ordering — some jurisdictions restrict online ammunition purchases or impose waiting periods.
- This ammunition contains lead; wash hands after handling and follow California Proposition 65 warnings if you reside in California.
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