300 Blackout Ammo

Supersonic vs. Subsonic: The .300 Blackout Advantage

.300 Blackout uniquely offers two completely different performance profiles in the same platform. Supersonic loads (110–125 grain at 2,100–2,350 fps) deliver .30-30-class energy for hunting and general-purpose use with a significant velocity advantage over pistol calibers. Subsonic loads (190–220 grain at 1,000–1,050 fps) reduce noise substantially when used with a suppressor — producing energy comparable to .45 ACP from the same rifle. Both load types cycle the same AR-15 action reliably with an appropriate gas system. This dual-mode capability is the core design feature that distinguishes .300 Blackout from every other AR-15 caliber.

Suppressor Use: The Primary Use Case

.300 Blackout in subsonic configuration with a suppressor is one of the quietest centerfire rifle setups available. Subsonic loads eliminate the supersonic crack; the suppressor handles the muzzle blast. From a 9-inch SBR barrel with a quality suppressor, the result is hearing-safe for most shooters without additional protection. Federal 220gr Open Tip, Hornady 208gr A-MAX Subsonic, and Remington 220gr OTM are reliable suppressor loads that cycle AR-15 actions consistently. Since January 1, 2026, the NFA tax stamp has been eliminated — see our suppressors page and ATF eForms guide for the registration process.

Barrel Length Guide: Short vs. Standard

Barrel length significantly affects .300 Blackout performance. A 9-inch barrel is the sweet spot for suppressed subsonic builds — short enough for extreme compactness, and subsonic loads don't benefit meaningfully from longer barrels. For supersonic loads, a 16-inch barrel extracts full velocity from the cartridge and keeps the build as a legal rifle without NFA registration. An 8-10-inch barrel with supersonic loads loses meaningful velocity versus 16 inches, but many SBR builders accept that tradeoff for compact overall length. For an unsuppressed hunting or general-purpose build, 16 inches is the right length. For a suppressed SBR, 9–10 inches is the most common configuration.

Hunting Loads

Supersonic .300 Blackout loads are capable of taking deer, hogs, and similar game inside 150 yards. Hornady 110gr V-MAX, Federal 120gr Fusion, and Barnes 110gr TAC-TX are purpose-designed expanding loads that expand reliably at .300 Blackout velocities. The cartridge performs best at ranges inside 200 yards — its ballistic coefficient drops off more rapidly than .308 or 6.5 Creedmoor at distance. For short-to-moderate range hunting from a compact platform, it's an excellent choice. Check state regulations — some states have minimum energy or caliber requirements for deer hunting that .300 Blackout may or may not meet depending on the load.

.300 Blackout vs. .223/5.56: When to Choose Which

.223/5.56 is lighter, less expensive, produces less recoil in a standard-pressure loading, and is available in a much wider range of factory loads. .300 Blackout delivers meaningfully more energy at short to moderate range, is the only AR-15 caliber with genuine subsonic suppressor capability, and requires only a barrel swap to run in a 5.56 lower. For most AR-15 users who don't own a suppressor and aren't hunting, .223/5.56 is the right choice. For suppressor hosts, hog hunters who want more energy in a compact platform, or anyone building a dedicated SBR, .300 Blackout justifies its cost premium. See our .223/5.56 ammo page for comparison.

AR-15 Compatibility: What Changes and What Doesn't

.300 Blackout uses a standard .223/5.56 bolt, carrier, lower receiver, and magazines — only the barrel changes. This makes converting an existing AR-15 to .300 Blackout a straightforward swap. The critical safety note: never chamber .300 Blackout in a .223/5.56 barrel. The .300 Blackout cartridge will chamber and fire in a .223 barrel but will destroy the barrel and can cause serious injury. In a household with both calibers, dedicated magazines labeled by caliber are essential to prevent mix-ups. Many .300 Blackout builders keep their .300 BLK magazines in a distinct color or with visible markings for this reason.

Pricing and Availability

.300 Blackout is priced higher than .223/5.56 but lower than most centerfire hunting calibers. Supersonic FMJ loads run approximately $0.60–$1.00 per round; subsonic loads run $1.00–$1.50 due to the heavier projectile. Federal, Hornady, Remington, and SIG all produce civilian-market .300 Blackout regularly. Buying subsonic loads in quantity when available is advisable — they sell out faster than supersonic loads and are less consistently stocked by retailers due to more limited overall demand.

Shop .300 Blackout Ammo at Impact Guns

Browse the full .300 Blackout ammunition selection at Impact Guns. For .300 Blackout AR-15 builds and complete rifles, see our AR-15 rifles page. For AR-15 pistols and SBR-format .300 Blackout builds, see our AR-15 pistols page. For suppressor options, see our suppressors page.