Mitchell Defense 7.5″ .300 Blackout SBR

Mitchell Defense Firearm Product Gallery Photo 048

$1,950.00 – $2,611.00

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Mission Brief

Backordered items will ship in November 2026

The Mitchell Defense 7.5″ .300 Blackout SBR is optimized for compact suppressed performance. Featuring a fast 1:5 twist barrel, adjustable gas system, B5 Systems stock, and Armorlube-coated MD Carbon Cutter BCG, it delivers reliable operation with subsonic ammunition.

Pistol Version Also Available Here

Why Choose the Mitchell Defense 7.5" .300 BLK SBR

• Optimized for Suppressed Subsonic Use – Designed to cycle reliably with heavy subsonic ammunition.

• Fast 1:5 Twist Barrel – Stabilizes heavier projectiles commonly used in .300 Blackout suppressed setups.

• Adjustable Gas System – Allows tuning for suppressed use and ammunition variations.

• B5 Systems Stock – Provides a stable shoulder interface and consistent cheek weld.

• Armorlube-Coated MD Carbon Cutter BCG – Reduced friction and improved reliability in suppressed environments.

• Lightweight Recoil System – Optimized buffer and spring for subsonic performance.

Built for Suppressed Performance

The Mitchell Defense 7.5" .300 Blackout SBR is engineered specifically for suppressed shooting applications. Every component is selected to ensure reliable operation with subsonic ammunition.

1:5 Twist Barrel for Heavy Projectiles

The fast 1:5 twist rate is designed to stabilize heavy .300 Blackout projectiles, ensuring consistent performance when using subsonic ammunition.

Adjustable Gas System

The adjustable gas system allows the rifle to be tuned for suppressed operation. This helps reduce excess gas while maintaining reliable cycling.

Armorlube-Coated MD Carbon Cutter Bolt Carrier Group

The MD Carbon Cutter bolt carrier group features an Armorlube coating that reduces friction, enhances lubricity, and improves corrosion resistance. This promotes smooth cycling under suppressed conditions.

Lightweight Recoil System

The lightweight buffer and spring system are designed to function with lower-pressure subsonic ammunition, helping maintain reliable cycling and smooth operation.

B5 Systems Stock

The B5 Systems stock provides a stable shooting platform and consistent cheek weld, improving control and repeatability.

Why Choose a 7.5" .300 Blackout Barrel?

The .300 Blackout cartridge was specifically designed to perform efficiently in short barrels, making the 7.5" configuration one of the most effective compact setups available.

Compared to a 10.3" .300 Blackout rifle, the 7.5" platform offers a smaller footprint while maintaining strong performance with subsonic ammunition.

Short barrel configurations pair exceptionally well with suppressors when using subsonic loads, making this setup highly effective for compact suppressed applications.

For shooters prioritizing maximum compactness and suppressed performance, the 7.5" configuration is one of the most efficient options available.

.300 Blackout Velocity and Performance

The .300 Blackout cartridge is designed to perform efficiently in short barrels, particularly when used with subsonic ammunition. Unlike traditional rifle calibers, it maintains consistent performance even as barrel length decreases.

Subsonic ammunition typically operates just below the speed of sound, generally around 950–1,050 fps, depending on load and environmental conditions. This makes it well suited for suppressed applications where reducing sound signature is a priority.

Supersonic .300 Blackout ammunition provides increased velocity and energy, typically ranging from approximately 1,900–2,200 fps depending on barrel length and projectile weight.

Barrel Length Subsonic Velocity Supersonic Velocity Performance Characteristics
7.5" ~950–1,050 fps ~1,900–2,100 fps Maximum compactness, optimized for suppressed subsonic use
10.3" ~1,000–1,100 fps ~2,000–2,200 fps Increased velocity and improved versatility

Shorter barrel configurations such as 7.5" maximize compactness while maintaining efficient subsonic performance, while slightly longer barrels like 10.3" provide improved velocity and flexibility when running both subsonic and supersonic ammunition.

Best Barrel Length for a Compact Suppressed Rifle

When building a compact suppressed rifle, barrel length plays a critical role in both handling and performance.

Rifle Barrel Length Comparison by Use Case

Use Case Recommended Barrel Length Why It Works
Close Quarters / Vehicle Use 10.3" 5.56 SBR Maximum maneuverability in confined spaces
General Purpose / Duty Rifle 11.5" 5.56 SBR Balanced performance and reliability
Patrol Rifle / Compact Performance 12.5" 5.56 SBR Increased velocity while compact
Duty / Patrol Rifle 14.5" 5.56 Rifle Smooth recoil and strong performance
Full-Length Performance 16" 5.56 Rifle Maximum velocity and consistency
Suppressed Compact Rifle 7.5" .300 BLK SBR Optimized for subsonic suppressed use
Balanced Suppressed Platform 10.3" .300 BLK SBR Improved suppressed performance

.300 Blackout vs 5.56 for Short Barrel Platforms

Feature .300 Blackout 5.56 NATO
Performance in Short Barrels Designed for efficient performance in short barrels Performance decreases as barrel length shortens
Suppressed Use Excellent with subsonic ammunition Typically louder when suppressed
Bullet Weight Heavy projectiles commonly 190–220 grains Lighter projectiles typically 55–77 grains
Sound Signature Reduced sound when using subsonic ammunition and suppressor Louder due to higher velocity
Ideal Use Compact suppressed platforms General-purpose rifles

If your priority is a compact suppressed platform, .300 Blackout offers significant advantages in short barrel configurations.

Product Description

The Mitchell Defense 7.5" .300 Blackout SBR is built for shooters who require a compact rifle optimized for suppressed performance.

The 7.5-inch CrMoV barrel features a fast 1:5 twist rate designed to stabilize heavy subsonic projectiles commonly used with suppressors.

The rifle operates on a direct impingement system with a pistol-length adjustable gas system, allowing fine tuning for ammunition and suppressor configurations.

Combined with the Armorlube-coated MD Carbon Cutter bolt carrier group and lightweight recoil system, the rifle delivers smooth and reliable operation.

Finished with B5 Systems furniture and a QD sling mount end plate, the Mitchell Defense 7.5" .300 Blackout SBR provides a compact and highly specialized rifle platform.

Specifications

Country of Origin: USA

Caliber: .300 Blackout

Barrel Length: 7.5 inches

Barrel Material: CrMoV Steel

Twist Rate: 1:5

Weight: 5.5 lbs

Gas System: Direct Impingement (Adjustable)

Gas Length: Pistol Length

Bolt Carrier Group: MD Carbon Cutter BCG – Armorlube Coated

Charging Handle: Reptilia Puller Charging Handle

Safety Selector: Radian Talon Ambidextrous

Bolt Release: Ambidextrous

Buffer System: Lightweight Buffer Spring

Buffer Weight: Lightweight Buffer

Trigger: High-Quality Two-Stage Trigger

Furniture: B5 Systems

Stock: B5 Systems Stock

End Plate: QD Mount End Plate