300 Blackout Range: Ballistics, Barrels, and Platforms

The .300 AAC Blackout, also known as 300 Blackout or 300 BLK, was developed to give AR-15 users a true .30-caliber option without major parts changes. It performs exceptionally well in short barrels and suppressed setups because it supports both supersonic and subsonic loads.

Use a 1:7 or 1:8 twist for heavy subsonic bullets, prefer 9 to 16-inch barrels for short or compact rifles, and always confirm your load with a chronograph and ballistic calculator.

• Supersonic: Lighter bullets (about 110 to 150 gr), flatter trajectory, effective out to about 200 to 300 yards depending on the load and ballistic coefficient.
• Subsonic: Heavy bullets (about 185 to 220 gr), below the speed of sound (around 1,100 to 1,150 fps), best for suppressed short-range shooting out to 100 to 150 yards.
• Best Barrels: 9 to 10.5 inches for compact suppressed rifles or SBRs, 12 to 16 inches for general use or hunting.
• Recommended Twist: 1:7 to 1:8 stabilizes 200 to 220 gr subsonic bullets. 1:10 works for lighter supersonic loads.
• Effective Range: Generally 100 to 300 yards depending on ammunition and shooter proficiency.
  
  

The .300 AAC Blackout is a .30-caliber cartridge that functions in standard AR-15 magazines and uses the same bolt face as 5.56 NATO.

It was designed to deliver better short- to medium-range performance, work efficiently from short barrels, and provide reliable operation when suppressed.

The cartridge became popular for three main reasons:

• Compatibility with AR-15 components with only a barrel change required
• Strong performance from short barrels and suppressed setups
• Flexibility to shoot both supersonic and subsonic ammunition from the same firearm
  
  

The 300 Blackout was developed in the late 2000s to meet the need for a 30-caliber round compatible with AR-15 platforms. The design focused on maximizing performance in short barrels while retaining full magazine capacity and standard bolt operation.

While specific inventors are sometimes named, cite only verified sources if including them in published material.

Supersonic 300 Blackout

• Bullet Weights: Typically 110 to 150 grain
• Muzzle Velocity: Around 2,000 to 2,450 fps depending on barrel length and load
• Ballistics: flatter Trajectory and longer reach than subsonic loads
• Use Cases: Hunting, target shooting, and general range work

Subsonic 300 Blackout

• Bullet Weights: Typically 185 to 220 gr, with 200 to 220 gr being most common
• Muzzle Velocity: Kept below the speed of sound, usually around 900 to 1,050 fps
• Ballistics: Heavier bullets maintain energy but have more drop and wind drift
• Use Cases: Suppressed shooting and close- to medium-range use

Shooters Tip
If switching between supersonic and subsonic loads, re-zero your optic or maintain separate profiles. The point of impact will shift significantly.

Ballistic coefficient (BC) indicates how efficiently a bullet cuts through air. The higher the BC, the better the bullet resists drag.

Typical BC ranges for 300 Blackout bullets:

• Light Supersonic Bullets (110 to 125 grain): BC around 0.18 to 0.28
• Midweight Supersonic Bullets (135 to 150 grain): BC around 0.25 to 0.35
• Heavy Subsonic Bullets (185 to 220 grain): BC around 0.30 to 0.60 depending on bullet shape

Always use the manufacturer’s published BC for your exact bullet and verify velocity with a chronograph. Enter both into a ballistic calculator for accurate drop and wind predictions.

Effective range

• Subsonic Suppressed: Typically effective out to about 100 to 150 yards
• Supersonic: Effective out to about 200 to 300 yards depending on bullet BC and skill
• Testing: Always confirm actual velocity and point of impact with your firearm, as factory data can vary with barrel length and conditions
  
  

Sportsman’s Select (Reman)

Sportsman’s Select remanufactured ammunition offers budget-friendly .300 Blackout ammo for high-volume range use and training. Their reman 300 BLK loads deliver reliable feeding and consistent performance at a value price, making them a smart option for shooters who want affordable practice rounds without sacrificing function.

US Cartridge (USC)

US Cartridge provides dependable, value-driven 300 Blackout ammo aimed at range shooters and trainers. USC’s 300 BLK offerings focus on consistent velocity and reliable cycling in AR-platform rifles, with options that suit both supersonic training and suppressed subsonic practice.

Sig Sauer

Sig Sauer’s ammunition division produces premium .300 Blackout ammo engineered to the company’s exacting standards. Sig’s 300 BLK lineup emphasizes accuracy and terminal performance, offering precision match-style loads and purpose-built subsonic/suppressed options for tactical and hunting builds.

Winchester

Winchester’s 300 Blackout offerings span both range-ready and hunting-grade loads, delivering consistent Winchester reliability across supersonic and heavy-subsonic profiles. Winchester 300 BLK ammo is popular for shooters who want proven feeding, good accuracy, and a wide selection of bullet types for training or field use.

Federal

Federal produces a broad selection of .300 Blackout ammo, from economical range rounds to premium hunting and defensive loads. Federal’s 300 BLK lines are designed for dependable ignition, reliable cycling in AR-style platforms, and effective terminal performance in both supersonic and subsonic configurations.

Hornady

Hornady’s 300 Blackout ammo is built around precision and advanced bullet technology, with purpose-driven options for hunting, tactical use, and suppressed shooting. Hornady’s 300 BLK lineup is known for high-BC projectiles and specially tuned subsonic loads, making it a go-to choice for long-range accuracy and controlled expansion.

The 300 Blackout was designed primarily for the AR-15 platform but is available in other firearm types as well.

Common platforms

• AR-15 (Dedicated Upper): Only requires a barrel change. Magazines and bolt face remain standard.
• AR Pistols and SBRs: Ideal for suppressed builds and short-range use.
• Bolt-action Rifles: Available for those who prefer precision or simplicity.
• Other Platforms: Less common due to feeding and magazine limitations.

Setup Notes

For suppressed builds, pair a short barrel with heavy subsonic bullets and a tuned gas system. In bolt guns, select a twist rate that matches your heaviest intended load.

Barrel Lengths

• 9 to 10.5 Inches: Best for compact suppressed rifles or SBRs; maintains good velocity for supersonic and excellent control for subsonic.
• 12 to 16 Inches: Balanced performance for general shooting or hunting.
• 20 Inches or More: Rare and unnecessary because velocity gains diminish beyond 16 inches.

Twist Rates

• 1:7 or 1:8: Best for stabilizing heavy subsonic bullets (200 to 220 gr).
• 1:10: Works for lighter supersonic loads but may not stabilize the heaviest bullets.

Choose a twist rate based on the heaviest ammunition you plan to shoot.

• Use a chronograph to confirm your velocity.
• Plug actual velocity and BC into a ballistic calculator to generate accurate data.
• If shooting suppressed, use an adjustable gas block to fine-tune function between load types.
• Re-zero your optic when changing between supersonic and subsonic ammunition.
• Confirm that your hunting loads meet local legal energy or caliber requirements.
  
  

Question: Is 300 Blackout good when suppressed?
Answer: Yes. 300 Blackout is one of the best suppressed cartridges available. With heavy subsonic bullets around 200 to 220 gr, it offers quiet operation and solid terminal performance.

Question: What barrel length works best for 300 Blackout?
Answer: Use a 9 to 10.5-inch barrel for suppressed compact setups, or 12 to 16 inches for hunting and general range use.

Question: Can I use my AR-15 magazines and bolt with 300 Blackout?
Answer: Yes. The cartridge was designed to work with standard AR-15 magazines and bolts. Only a barrel change is required.

Question: Should I use a 1:7 or 1:10 twist?
Answer: Choose 1:7 or 1:8 if you plan to shoot heavy subsonic loads. A 1:10 works for lighter supersonic ammunition.