Reliable 300 AAC Blackout reloading data is published in established manuals from Hodgdon, Hornady, Sierra, and the Lyman AR Reloading Handbook. Published data normally includes the specific 0.308-inch bullet design, powder type, starting and maximum charge weights, expected muzzle velocity, and cartridge overall length. Common bullet weights covered by published 300 AAC Blackout load data range from lightweight 110-grain supersonic projectiles up to heavy 220-grain subsonic match bullets. Results will naturally vary between sources due to differences in the exact bullet profile, powder burn rate, brass case capacity, test barrel length, and atmospheric testing conditions.
300 AAC Blackout Reloading Data
| Bullet | Bullet Weight | Powder | Published Starting Load | Published Maximum Load | Published Velocity | Pressure (Max) | Primer & Case | Cartridge Overall Length (COL) | Barrel Length / Firearm | Source |
| Hornady V-MAX | 110 grain | Hodgdon H110 | 18.8 gr | 20.0 gr | 2,382 fps | 50,600 CUP | Small Rifle / Hornady | 2.040″ | 16.00″ / Universal | Hodgdon |
| Hornady V-MAX | 110 grain | Hodgdon Lil’ Gun | 18.9 gr | 20.0 gr | 2,388 fps | 37,600 CUP | Small Rifle / Hornady | 2.040″ | 16.00″ / Universal | Hodgdon |
| Nosler BT | 125 grain | Winchester 296 | 16.7 gr | 17.8 gr | 2,118 fps | 48,800 CUP | Small Rifle / Hornady | 2.060″ | 16.00″ / Universal | Hodgdon |
| Sierra HPBT | 135 grain | Hodgdon H110 | 17.3 gr | 18.4 gr | 2,109 fps | 51,200 CUP | Small Rifle / Hornady | 2.120″ | 16.00″ / Universal | Hodgdon |
| Sierra HPBT | 135 grain | Hodgdon Lil’ Gun | 16.5 gr | 18.0 gr | 2,127 fps | 43,200 CUP | Small Rifle / Hornady | 2.120″ | 16.00″ / Universal | Hodgdon |
| Hornady FMJ-BT | 150 grain | IMR 4227 | 15.3 gr | 16.2 gr | 1,870 fps | 51,700 CUP | Small Rifle / Hornady | 2.140″ | 16.00″ / Universal | Hodgdon |
| Hornady Sub-X | 190 grain | Hodgdon CFE BLK | 10.8 gr | 12.0 gr | 1,050 fps | Not Listed | Small Rifle / Federal | 2.070″ | 16.00″ / AR-15 | Hornady / Ultimate Reloader |
| Hornady ELD Match | 208 grain | Hodgdon CFE BLK | 11.2 gr | 12.2 gr | 1,020 fps | Not Listed | Small Rifle / Hornady | 2.260″ | 16.00″ / Universal | Hornady |
| Sierra HPBT | 220 grain | Hodgdon H110 | 9.9 gr | 9.9 gr | 1,050 fps | 29,700 CUP | Small Rifle / Hornady | 2.260″ | 16.00″ / Universal | Hodgdon |
| Sierra HPBT | 220 grain | Accurate 1680 | 10.8 gr | 11.2 gr | 1,050 fps | Not Listed | Small Rifle / Hornady | 2.260″ | 16.00″ / Universal | Western Powders |
Understanding The 300 AAC Blackout Reloading Data
To safely develop a 300 AAC Blackout load recipe, handloaders must understand the distinct variables in published data, particularly the strict division between supersonic and subsonic loads:
- Starting load: The minimum safe powder charge. For supersonic loads, reloaders must start here and work up. For subsonic loads, starting loads are often very close to maximum loads to ensure reliable cycling without exceeding the speed of sound.
- Maximum published load: The maximum safe pressure limit tested by a ballistic laboratory, or the maximum charge that keeps the heavy bullet subsonic.
- Velocity: The speed of the bullet in feet per second (fps). The speed of sound is roughly 1,125 fps; subsonic loads are intentionally kept below 1,050 fps to completely eliminate the sonic crack.
- Pressure: The 300 AAC Blackout has a SAAMI maximum average pressure limit of 55,000 PSI.
- Bullet weight: The mass of the 0.308-inch projectile in grains.
- Powder: The specific propellant type. The 300 AAC Blackout requires fast-burning rifle powders or magnum pistol powders.
- Barrel length: Test barrels for 300 AAC Blackout are typically 16 inches in major manuals, though the cartridge is highly optimized for 8-inch to 10-inch barrels.
- Firearm used for testing: Universal receiver test barrels or production AR-15 platforms.
- Test conditions: Altitude, humidity, and temperature variables during pressure testing.
- Cartridge overall length (COL): The total length of the loaded cartridge. Due to AR-15 magazine restrictions and the cartridge’s unique feed ramp geometry, strictly adhering to the published COL is critical to prevent feeding jams.
Different published sources produce varying results due to differing powder lots, thicker brass case walls (which reduce internal capacity and spike pressure), and tighter chamber tolerances.
300 AAC Blackout Bullet Weight Reloading Data
300 AAC Blackout reloading data is categorized into two distinct groups: lightweight bullets driven to supersonic speeds, and heavy bullets designed for subsonic suppression. The cartridge uses standard 0.308-inch rifle bullets.
- 110 grain to 125 grain: The most popular weights for supersonic hunting and self-defense. Bullets like the 110-grain Hornady V-MAX or 125-grain Nosler Ballistic Tip can be driven between 2,100 fps and 2,400 fps from a 16-inch barrel, offering excellent terminal expansion.
- 135 grain to 150 grain: Mid-weight projectiles commonly used for plinking, target shooting, and medium-game hunting. The 150-grain FMJ is a popular, inexpensive bullet choice, achieving around 1,800 to 1,900 fps.
- 190 grain to 200 grain: The entry point for subsonic loads. The Hornady 190-grain Sub-X is heavily documented in reloading manuals because it is specifically designed to expand at low subsonic velocities (around 1,000 fps), unlike traditional match bullets.
- 208 grain to 220 grain: The gold standard for heavy subsonic 300 AAC Blackout reloading data. Heavy match bullets (like the 220-grain Sierra MatchKing or 208-grain ELD Match) provide the necessary length and mass to reliably cycle an AR-15’s gas system while remaining whisper-quiet through a suppressor.
Do not assume a bullet designed for the .308 Winchester will automatically perform well in the 300 AAC Blackout. Most heavy .30 caliber hunting bullets will not expand at 300 AAC Blackout subsonic velocities, acting instead like a solid full metal jacket.
300 AAC Blackout Powder Reloading Data
The 300 AAC Blackout relies on fast-burning powders that achieve a complete burn inside very short barrels.
| Powder | Bullet | Bullet Weight | Published Starting Load | Published Maximum Load | Published Velocity | Source |
| Hodgdon H110 | Hornady V-MAX | 110 grain | 18.8 gr | 20.0 gr | 2,382 fps | Hodgdon |
| Hodgdon Lil’ Gun | Sierra HPBT | 135 grain | 16.5 gr | 18.0 gr | 2,127 fps | Hodgdon |
| Hodgdon CFE BLK | Hornady ELD-M | 208 grain | 11.2 gr | 12.2 gr | 1,020 fps | Hornady |
| Winchester 296 | Nosler BT | 125 grain | 16.7 gr | 17.8 gr | 2,118 fps | Hodgdon |
| IMR 4227 | Hornady FMJ | 150 grain | 15.3 gr | 16.2 gr | 1,870 fps | Hodgdon |
Never mix supersonic and subsonic powder applications carelessly. Powders like Hodgdon CFE BLK and Accurate 1680 are heavily favored for 220-grain subsonic loads because they generate enough port pressure to cycle an AR-15 bolt carrier group. Extremely fast powders (like H110) are excellent for lightweight supersonic bullets but can sometimes struggle to reliably cycle an AR-15 gas system when down-loaded for heavy subsonics.
300 AAC Blackout Bullet And Powder Combinations
Safe 300 AAC Blackout load development relies on carefully matching components to the rifle’s intended purpose.
- Case capacity and bullet seating depth: The 300 AAC Blackout has a very small internal powder capacity. Seating a long, heavy 220-grain bullet slightly deeper than the published COL drastically compresses the powder charge and aggressively spikes chamber pressure.
- Bullet profile and feeding: The AR-15 feed ramps were originally designed for 5.56 NATO. Blunt, round-nose .30 caliber bullets often catch on the feed ramps. Reloaders should stick to polymer-tipped or sleek boat-tail hollow points proven in published 300 AAC Blackout load data to ensure reliable semi-automatic feeding.
- Primer: The cartridge uses small rifle primers. In AR-15 platforms with floating firing pins, using thin-cupped pistol primers can lead to dangerous slam-fires.
- Crimp: A light taper crimp or factory crimp is recommended to prevent bullets from being set back into the case during feeding.
- Gas system compatibility: If loading subsonic ammunition for an AR-15, pistol-length gas systems are strongly recommended. Carbine-length gas systems often fail to cycle subsonic loads reliably.
300 AAC Blackout Velocity From Published Data
Published 300 AAC Blackout velocity figures reflect laboratory conditions utilizing 16-inch barrels.
| Bullet | Bullet Weight | Powder | Published Load | Muzzle Velocity | Barrel Length | Firearm | Source |
| Hornady V-MAX | 110 grain | H110 | 20.0 gr (Max) | 2,382 fps | 16.00″ | Universal Receiver | Hodgdon |
| Sierra HPBT | 135 grain | Lil’ Gun | 18.0 gr (Max) | 2,127 fps | 16.00″ | Universal Receiver | Hodgdon |
| Hornady Sub-X | 190 grain | CFE BLK | 12.0 gr (Max) | 1,050 fps | 16.00″ | AR-15 Platform | Ultimate Reloader |
Shooters must distinguish between manufacturer-published velocities and independent chronograph testing. Handloaders firing the same 110-grain H110 max load through an 8-inch barrel will generally measure velocities closer to 2,100 fps rather than the laboratory’s 2,382 fps.
300 AAC Blackout Reloading Data By Barrel Length
The 300 AAC Blackout was engineered to achieve a complete powder burn in roughly 9 inches of barrel length. Consequently, barrel length affects 300 AAC Blackout velocity far differently than traditional bottleneck rifle cartridges.
When firing supersonic ammunition, reducing the barrel length from 16 inches down to 8 inches typically results in a velocity loss of only 200 to 250 fps. For subsonic ammunition, barrel length has minimal impact on terminal speed, as the powder charge is specifically tailored by the reloader to keep the bullet hovering just below the 1,050 fps threshold regardless of the barrel length. Reloaders must clearly identify the test firearm and barrel length when referencing velocity, as subsonic loads tuned for a 16-inch barrel may exit an 8-inch barrel at 900 fps, causing cycling issues.
300 AAC Blackout Energy And Ballistics
The 300 AAC Blackout delivers vastly different terminal ballistics depending on whether supersonic or subsonic data is utilized.
- Supersonic Ballistics (110-grain V-MAX at 2,350 fps):
- Muzzle energy: ~1,349 ft-lbs
- 100-yard velocity: ~2,010 fps
- 100-yard energy: ~987 ft-lbs
- Subsonic Ballistics (208-grain ELD Match at 1,020 fps):
- Muzzle energy: ~480 ft-lbs
- 100-yard velocity: ~987 fps
- 100-yard energy: ~450 ft-lbs
While subsonic loads are exceptionally quiet when suppressed, they possess a steep trajectory and shed kinetic energy rapidly. For ethical medium-game hunting past 100 yards, supersonic loads are vastly superior.
Manufacturer Data vs Independent Testing
Reloaders consulting a 300 AAC Blackout load data chart will encounter:
- Manufacturer-published reloading data: Officially pressure-tested in a laboratory using piezo-electric sensors to guarantee loads stay safely under the 55,000 PSI limit.
- Independent chronograph testing: Velocities recorded by shooters using commercial chronographs. This verifies speed and firearm cycling but cannot measure internal chamber pressure.
- User-submitted load reports: Internet forum recipes that often ignore critical gas system length differences and COL variations.
Independently measured results frequently differ from published data because consumer AR-15s feature varying gas port sizes, buffer weights, and suppressor back-pressure variables. Priority must always remain with official, pressure-tested manufacturer limits.
300 AAC Blackout Pressure And Safety
Safety is paramount when using 300 AAC Blackout reloading data due to one uniquely hazardous cartridge characteristic: the 300 AAC Blackout shares the exact same case head dimension and magazine format as the 5.56 NATO.
Loading a 300 AAC Blackout cartridge into a 5.56 NATO chamber will result in a catastrophic, firearm-destroying explosion. Reloaders must meticulously label magazines and segregate 300 AAC Blackout ammunition from 5.56 NATO.
Furthermore, because the 300 AAC Blackout has a 55,000 PSI limit and uses fast-burning pistol powders, a double charge of powder will fit easily inside the case and destroy the rifle. Reloaders must never use load data developed for different .30 caliber cartridges (like the .308 Winchester or 7.62×39) as the powders and case volumes are entirely incompatible.
Best Sources For 300 AAC Blackout Reloading Data
The most authoritative sources for safe 300 AAC Blackout load development include:
- Hodgdon Reloading Data Center: Provides the most extensive, free online data specifically highlighting supersonic powders (H110, Lil’ Gun) and subsonic specialists (CFE BLK).
- Hornady Handbook of Cartridge Reloading: Offers incredibly comprehensive component specificity for their 190-grain Sub-X, 208-grain A-MAX/ELD, and V-MAX bullets.
- Lyman AR Reloading Handbook: A dedicated manual containing pressure-tested data tailored exclusively for the AR-15 platform.
- Sierra Bullets Manual: Publishes excellent subsonic load data for their heavy MatchKing projectiles.
Common 300 AAC Blackout Reloading Data Questions
Where can I find 300 AAC Blackout reloading data?
Authoritative data is available in the Hornady Reloading Handbook, the Lyman AR Reloading Handbook, and free online via the Hodgdon Reloading Data Center.
What powders are used in published 300 AAC Blackout data?
Common powders include Hodgdon H110, Lil’ Gun, CFE BLK, Winchester 296, IMR 4227, and Accurate 1680.
What bullet weights have 300 AAC Blackout reloading data?
Published data covers lightweight 110-grain to 150-grain supersonic projectiles, and heavy 190-grain to 220-grain subsonic bullets.
What is the best source for 300 AAC Blackout reloading data Hodgdon?
The official Hodgdon Reloading Data Center provides the most rigorously pressure-tested data for all Hodgdon, IMR, and Winchester brand powders.
Why does 300 AAC Blackout reloading data vary between sources?
Variations occur due to the massive spectrum of bullet profiles, differences in test barrel lengths (16-inch vs short-barreled rifles), and different brass case wall thicknesses.
Does barrel length affect 300 AAC Blackout velocity?
Yes, but less severely than bottleneck rifle cartridges. Moving from a 16-inch barrel down to an 8-inch barrel typically drops supersonic velocity by only 200 to 250 fps.
Can the same powder charge be used with a different bullet?
No. Different bullet profiles, materials, and bearing surfaces alter internal case capacity and friction, which dramatically changes chamber pressures.
What is the difference between starting and maximum published load data?
The starting load is the safe baseline for working up a new recipe. The maximum load is the highest pressure limit established safely by a ballistic laboratory.
Where can I find pressure-tested 300 AAC Blackout data?
Pressure-tested data is available directly from major bullet and powder manufacturers, including Hornady, Hodgdon, Sierra, and Lyman.
Does Hodgdon publish 300 AAC Blackout reloading data?
Yes. Hodgdon provides extensive data specifically developed for the cartridge, including their flagship CFE BLK subsonic powder and H110 supersonic powder.
Does Hornady publish 300 AAC Blackout reloading data?
Yes. Hornady publishes data tailored specifically for their 0.308-inch projectiles, including the highly popular 190-grain Sub-X and 208-grain ELD Match.
Does Nosler publish 300 AAC Blackout reloading data?
Yes. Nosler publishes data for their Ballistic Tip and Custom Competition bullets, which perform excellently in supersonic 300 AAC Blackout configurations.