| Load | Type | Bullet Weight | Velocity | Energy | Cost | Sound Level | Best For |
|---|---|---|---|---|---|---|---|
| Barnes VOR-TX 110gr TAC-TX | supersonic | 110 grains | 2350 fps | 1350 ft-lbs | $1.50/round | loud | Hunting deer/hogs to 150 yards |
| Hornady 110gr V-MAX | supersonic | 110 grains | 2375 fps | 1378 ft-lbs | $1.10/round | loud | Varmints and hog hunting to 100 yards |
| SIG Sauer 120gr Elite Copper | supersonic | 120 grains | 2250 fps | 1350 ft-lbs | $1.60/round | loud | Defense and medium game hunting |
| Hornady 125gr SST | supersonic | 125 grains | 2175 fps | 1313 ft-lbs | $1.20/round | loud | Whitetail deer hunting |
| Frontier/Hornady 125gr FMJ | supersonic | 125 grains | 2175 fps | 1313 ft-lbs | $0.50/round | loud | High-volume training and practice |
| Hornady 190gr Sub-X | subsonic | 190 grains | 1050 fps | 465 ft-lbs | $1.40/round | hearing-safe | Suppressed home defense and hog hunting |
| Hornady 208gr A-MAX | subsonic | 208 grains | 1020 fps | 480 ft-lbs | $1.60/round | hearing-safe | Quiet range time and subsonic precision |
| Lehigh Defense 194gr Maximum Expansion | subsonic | 194 grains | 1040 fps | 466 ft-lbs | $2.25/round | hearing-safe | Premium suppressed defensive use |
| Federal American Eagle 220gr OTM | subsonic | 220 grains | 1000 fps | 488 ft-lbs | $0.85/round | hearing-safe | Budget subsonic training |
| Gorilla 205gr Subsonic | subsonic | 205 grains | 1030 fps | 483 ft-lbs | $1.75/round | hearing-safe | Suppressed hunting and defense |
| Barrel Length | Supersonic Velocity | Subsonic Velocity | Powder Burn | Gas System | Best For |
|---|---|---|---|---|---|
| 5.5" | 1850 fps | 1000 fps | incomplete | pistol | PDW, vehicle gun, suppressor host |
| 7.5" | 2000 fps | 1010 fps | incomplete | pistol | PDW, suppressor host, truck gun |
| 8.3" | 2075 fps | 1015 fps | incomplete | pistol | PDW, suppressor host, home defense |
| 9" | 2125 fps | 1020 fps | optimal | pistol | suppressor host, home defense, duty |
| 10.3" | 2200 fps | 1030 fps | optimal | pistol | suppressor host, duty, hunting |
| 12.5" | 2275 fps | 1040 fps | complete | carbine | duty, hunting, general purpose |
| 16" | 2375 fps | 1050 fps | complete | carbine | rifle, hunting, non-NFA build |
The .300 AAC Blackout exists for one reason: to be the ultimate suppressed AR-15 cartridge. Designed from the ground up for short barrels and silencers, it delivers what 5.56 cannot— truly quiet subsonic capability with genuine terminal performance. This guide covers everything you need to build the perfect .300 BLK setup, from ammunition selection to suppressor pairing.
9"
The sweet spot. Complete powder burn, optimal suppressor performance, compact package. This is what .300 BLK was designed for.
Q Trash Panda
Purpose-built for .300 BLK. Excellent suppression, reasonable weight, quick-attach mount. The OG choice for dedicated hosts.
Hornady 190gr Sub-X
Flex Tip designed for reliable expansion at subsonic velocities. The best factory option for terminal performance.
The Problem: 5.56 NATO was designed for 20" barrels. Short barrels lose significant velocity, and the supersonic crack makes true suppression impossible.
The Solution: AAC developed .300 Blackout to deliver .30 caliber performance from short barrels while enabling genuine subsonic capability. Same bolt, same magazines—just swap the barrel.
The Result: A cartridge that achieves complete powder burn in 9" barrels, works flawlessly with suppressors, and fires subsonic rounds that are genuinely hearing-safe.
Compare loads, find optimal barrel lengths, and match suppressors.
This is THE decision that shapes your entire .300 BLK setup. Understanding the tradeoffs determines whether .300 BLK makes sense for you.
Supersonic .300 BLK is ballistically INFERIOR to 5.56. Read that again. If you're running supersonic loads without a suppressor, you're paying 2-3x per round for worse external ballistics than 5.56.
The ONLY reason to choose .300 BLK over 5.56: You want subsonic capability with a suppressor. Everything else is a compromise. If you don't own or plan to buy a suppressor, stick with 5.56.
When you need maximum terminal performance or extended range. Still loud even suppressed (sonic crack persists), but suppressor reduces blast significantly.
All-copper hollow point with aggressive expansion and 95%+ weight retention. Creates devastating wound channels.
Explosive fragmentation. Devastating on soft tissue but limited penetration.
Solid copper construction with controlled expansion. Maximum weight retention.
Polymer tip with Interlock ring for controlled expansion. Good weight retention.
The reason .300 BLK exists. Heavy bullets traveling below the speed of sound (~1,100 fps) eliminate the sonic crack, making suppressed fire genuinely quiet.
Flex Tip designed for reliable expansion at subsonic velocities. Penetrates 12-18" in gel.
Match bullet - not designed for expansion. Terminal performance similar to ball ammo.
Engineered to expand to 2x diameter at subsonic velocities. Creates massive wound cavity.
OTM - may expand but not designed for reliable terminal performance.
Unlike 5.56, .300 BLK was designed for short barrels. Here's exactly where each length shines.
Complete powder burn for most loads. Optimal suppressor performance. Compact enough for vehicle/CQB use.
~2,125 fps supersonic (110gr), ~1,020 fps subsonic (220gr). Within 5% of maximum velocity.
Suppressed builds, home defense, PDW, duty use. The default recommendation.
| Length | OAL Suppressed | Super Vel. | Sub Vel. | Powder | Best For |
|---|---|---|---|---|---|
| 5.5" | 28.5" | 1850 fps | 1000 fps | incomplete | PDW, vehicle gun |
| 7.5" | 30.5" | 2000 fps | 1010 fps | incomplete | PDW, suppressor host |
| 8.3" | 31.3" | 2075 fps | 1015 fps | incomplete | PDW, suppressor host |
| 9" | 32" | 2125 fps | 1020 fps | optimal | suppressor host, home defense |
| 10.3" | 33.3" | 2200 fps | 1030 fps | optimal | suppressor host, duty |
| 12.5" | 35.5" | 2275 fps | 1040 fps | complete | duty, hunting |
| 16" | 39" | 2375 fps | 1050 fps | complete | rifle, hunting |
Maximum concealability for PDW/vehicle gun use. Expect incomplete powder burn with supers (more flash, less velocity). Subs remain fully effective. Requires careful gas tuning for reliability.
Maximum velocity but defeats the purpose of .300 BLK. Only choose if you can't/won't SBR or use a pistol brace. At this point, consider if 5.56 makes more sense for your use case.
Here's what nobody talks about: you can't tune a gas system to run both supersonic and subsonic loads optimally. This is THE fundamental challenge of .300 Blackout.
Subsonic loads produce ~60% less gas pressure than supersonic loads. A gas system tuned to reliably cycle 220gr subs will be massively over-gassed when you switch to 110gr supers.
The result: When running supers on a sub-tuned gun, the bolt carrier slams back violently, beating the rifle to death, causing excessive wear, and creating punishing felt recoil. Conversely, tune for supers and your subs may short-stroke or fail to lock back.
Add a suppressor and it gets worse. The added back pressure makes an already over-gassed super even more violent. Remove the suppressor and your sub-tuned gun might not cycle at all.
The most common approach. Dial down gas for supers, dial up for subs.
Reality: Most people set it for subs and never touch it—accepting harsh super cycling.
Increase buffer weight (H2/H3) and use a heavier spring to slow bolt carrier velocity.
Reality: Better than nothing, but you're still living with a compromise.
The SIG MCX Rattler's piston system includes a two-position gas regulator that can be switched between "suppressed" (subs) and "unsuppressed" (supers) with a simple lever. No tiny screws, no tools, no counting clicks.
Why piston wins here: The gas system is self-contained in the handguard, isolated from the BCG. This makes gas adjustment more accessible and less prone to carbon fouling affecting the setting.
Caveat: Still recoils pretty hard with supers. The physics of a 5.5" barrel and light platform don't change. But it's the cleanest solution to the tuning problem.
Tune for subs suppressed. Accept that supers will cycle hard. Use H2/H3 buffer to soften the blow. This is what most suppressed .300 BLK builds end up being.
Tune for supers. Use adjustable gas block and accept that subs may not cycle without the suppressor. Best if you rarely shoot subs or always shoot suppressed.
Buy a SIG Rattler/MCX or accept that you'll need to adjust your gas block when switching. There's no free lunch with DI guns on this caliber.
.300 BLK was designed for suppression. Here are the top picks for different priorities.
Dedicated .300 BLK suppressor host. The OG choice.
When maximum suppression matters more than compactness.
Multi-host .30 caliber suppressor that excels on .300 BLK.
Absolute maximum suppression. Money-no-object choice.
Lightweight multi-caliber can with great .300 BLK performance.
Low back pressure priority. Best for gassy AR setups.
Low back pressure = less gas in your face, less bolt speed increase. Important for AR platforms. HUXWRX FLOW leads here.
Dead Air KeyMo is the industry standard for QD. Q Cherry Bomb is great but proprietary. Direct thread is lightest but slowest to attach.
Longer suppressors = quieter but heavier and less maneuverable. CGS Hyperion is quietest; Q Trash Panda is most balanced.
.300 BLK isn't cheap. Here's what you're actually signing up for.
Supersonic: $0.50-$1.60/round (vs $0.35 for 5.56)
Subsonic: $0.85-$2.25/round
Reality: Training with .300 BLK costs ~1.5-2x what 5.56 does—down from 2-3x a few years ago.
Annual cost (1500 rounds): ~$1,020 vs $525 for 5.56
Difference: ~$500/year in ammo alone
Good news: Prices have stabilized significantly since the 2020-2023 spike.
| Item | Budget | Mid-Range | Premium | Notes |
|---|---|---|---|---|
| Complete .300 BLK Upper | $350 | $650 | $1200 | PSA budget, BCM/Aero mid, DD/LWRC high-end |
| Barrel Only (9" .300 BLK) | $125 | $225 | $400 | BCA budget, Ballistic Advantage mid, Criterion high-end |
| Dedicated .30 Cal Silencer | $400 | $800 | $1400 | Form 1 DIY, Trash Panda mid, CGS Hyperion high-end |
| Tax Stamp | $200 | $200 | $200 | Required $200 NFA tax for suppressor or SBR |
| Tax Stamp (if SBR) | $200 | $200 | $200 | Required if barrel under 16" and using rifle stock |
| Supersonic (per 20 rounds) | $10 | $16 | $32 | Training FMJ to premium hunting ammo |
| Subsonic (per 20 rounds) | $17 | $24 | $45 | Budget plinking to premium defensive subs |
Reloading .300 BLK drops cost to ~$0.35/round supersonic, ~$0.42/round subsonic using converted 5.56 brass. Initial equipment investment ($400-800) pays for itself within 1,500-2,000 rounds. For serious .300 BLK shooters, reloading is almost mandatory.
A .300 Blackout round WILL chamber in a 5.56 barrel. When fired, the .308 bullet cannot exit the .224 bore. The result is catastrophic failure—destroyed rifle, potential severe injury or death.
This happens because both cartridges use the same parent case (.223 Remington). Standard AR-15 magazines feed both calibers without modification.
For deer hunting beyond 150 yards, consider 6.5 Grendel. .300 BLK trades range for suppression capability.
The honest answer: .300 BLK is a fantastic cartridge for its intended purpose— suppressed SBR use. Outside that niche, 5.56 does almost everything better for less money. Build .300 BLK as a dedicated suppressor host, not as a general-purpose rifle.
For in-depth analysis and testing, we recommend Brass Facts on YouTube—one of the best resources for honest, data-driven .300 Blackout content.
External links open in new tab. We're not affiliated with Brass Facts—just fans of quality content.
Our top picks for .300 BLK ammunition, suppressors, and accessories. All links go to OpticsPlanet for easy availability.
The gold standard for .300 BLK hunting. All-copper hollow point with 95%+ weight retention delivers devastating terminal performance on hogs and deer.
Explosive fragmentation makes this ideal for varmints and hogs where you want maximum tissue damage. Budget-friendlier than premium hunting loads.
The best factory subsonic for terminal performance. Flex Tip technology ensures reliable expansion at subsonic velocities—critical for defensive use.
Budget subsonic for high-volume training. Open tip match bullet won't expand reliably but cycles well suppressed and keeps costs manageable.
Standard training ammo for .300 BLK. FMJ loads from Frontier, Winchester, or Federal are your best bet for affordable range time.
Marked specifically for .300 BLK with a distinct visual pattern to prevent dangerous mix-ups with 5.56 magazines. Same polymer, same reliability—different markings.
Translucent smoke color provides round count visibility and differentiates from 5.56 mags. Steel feed lips for reliability.
Essential for running both subsonic and supersonic loads. Bleed-off design reduces gas without increasing felt recoil at lower settings.
Heavier buffer slows down bolt carrier velocity when running hot supersonic loads suppressed. Start with H2, move to H3 if still over-gassed.
Purchasing through these links may generate a commission at no extra cost to you. Prices fluctuate—verify current availability before ordering.
Ready to continue? Here's the recommended next guide:
Set up AR-15 suppressors correctly. Learn host preparation, backpressure management, POI shift tracking, mount selection, and overgassing fixes for reliable suppressed operation.
Or explore a related topic:
AR-15 Caliber Selection Guide 2025->Continue exploring with these related resources
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