Comstock Armory RPA Recessed Suppressor Adapter

Plan-B Compatible - Lightest Steel HUB Adapter - 2.1 oz The Comstock Armory RPA (Recessed Profile Adapter) is a recessed suppressor adapter compatible with Rearden and other common Plan-B muzzle devices. Currently the lightest recessed steel Plan-B HUB adapter on the market at just 2.1 ounces. Compared to the standard LPA, the RPA shortens the overall length of the suppressor system and creates a tighter handguard-to-suppressor gap. Manufactured from high-strength 17-4 PH stainless steel with durable black nitride finish. Features standard 1.375-24 threads (HUB/Bravo) for use on most rifle suppressors. Includes both 1-7/16" wrench flats and 1.5" spanner notches for easy installation and removal. Adds only 0.18" to overall length while positioning muzzle devices 0.40" deeper than standard LPA. Allows quick attachment and removal of suppressors with Plan-B compatible muzzle devices.

Recessed Profile Design

The recessed profile design shortens the overall length of the suppressor system compared to standard adapters. By positioning the muzzle device 0.40" deeper than the standard LPA (Low Profile Adapter), the RPA creates a more compact suppressor setup. This recessed design also produces a tighter handguard-to-suppressor gap, improving the visual integration and reducing overall system length.

Lightest Steel Plan-B HUB Adapter

At just 2.1 ounces, the RPA is currently the lightest recessed steel Plan-B HUB adapter available on the market. This minimal weight addition proves valuable for maintaining balance on suppressed rifles, particularly with lightweight builds or when running suppressors on carbines and SBRs where every ounce matters.

Plan-B Compatible

The RPA is compatible with Rearden and other common Plan-B muzzle devices. Plan-B is a popular taper-mount quick-detach system known for secure lockup and ease of use. The RPA enables use of the Plan-B ecosystem with HUB-threaded suppressors, providing flexibility in muzzle device selection.

17-4 PH Stainless Steel Construction

Manufactured from high-strength 17-4 PH (precipitation hardened) stainless steel, the RPA delivers exceptional strength and corrosion resistance. The 17-4 stainless provides superior mechanical properties compared to standard stainless grades, withstanding the heat, pressure, and stress of suppressor use while resisting environmental corrosion.

Black Nitride Finish

The durable black nitride finish enhances corrosion resistance and wear protection while reducing reflectivity. Nitride treatment penetrates the steel surface, creating exceptionally hard, lubricious coating that withstands carbon buildup, heat cycling, and environmental exposure. The black finish provides professional appearance and tactical discretion.

Standard HUB/Bravo Threading

The RPA features standard 1.375-24 threads, also known as HUB or Bravo threading. This universal suppressor mounting standard enables compatibility with most modern rifle suppressors. The HUB threading allows the RPA to interface with a wide variety of suppressors from different manufacturers.

Dual Tool Interface

The RPA includes both 1-7/16" wrench flats and 1.5" spanner notches for easy installation and removal. This dual tool interface accommodates different wrench types and sizes, ensuring users can achieve proper torque whether using an armorer's wrench, adjustable wrench, or spanner wrench. The multiple tool options simplify installation and maintenance.

Minimal Length Addition

The RPA adds only 0.18" to overall suppressor length. This minimal addition maintains the compact profile benefits of direct-thread mounting while providing the convenience and versatility of quick-detach capability. The short adapter length proves particularly valuable on short-barreled rifles where overall length matters.

Quick Attachment and Removal

The RPA allows for quick attachment and removal of suppressors when used with Plan-B compatible muzzle devices. The Plan-B taper-mount system enables tool-free installation and removal in seconds, proving valuable for training, transport, and situations requiring rapid suppressor deployment or removal.

Reduced Handguard Gap

By recessing the muzzle device 0.40" deeper than standard adapters, the RPA creates a tighter handguard-to-suppressor gap. This reduced gap improves aesthetics and can enable use of shorter handguards or tighter-fitting suppressors that might otherwise require longer handguard clearance.

Fitment Considerations

The RPA places muzzle devices 0.40" deeper than the standard LPA. Users should verify their muzzle device and suppressor combination will accommodate this deeper positioning. Some muzzle devices or suppressor internal configurations may not provide adequate clearance for the recessed design. Contact manufacturer for fitment verification if uncertain.

Alignment and Safety

Always use an alignment rod to ensure the suppressor system is set up correctly before live fire. Proper alignment prevents baffle strikes that can damage the suppressor and create dangerous conditions. Check bullet stabilization before attaching a suppressor to ensure projectiles remain stable through the suppressor baffles.

Warranty Considerations

Some suppressor manufacturers do not warranty their products when used on aftermarket mounts or muzzle devices. Verify warranty terms with your suppressor manufacturer before using aftermarket mounting solutions. The RPA is designed and manufactured to high standards but users assume responsibility for compatibility verification. The Comstock Armory RPA delivers recessed profile efficiency with Plan-B compatibility—the lightest steel solution for compact suppressor systems.

SPECIFICATIONS

• Manufacturer: Comstock Armory
• Model: RPA (Recessed Profile Adapter)
• Type: Suppressor Adapter/Mount
• Mounting System: Plan-B Compatible (taper-mount)
• Compatible Muzzle Devices: Rearden and other common Plan-B devices
• Material: 17-4 PH Stainless Steel (precipitation hardened)
• Finish: Black Nitride
• Thread Pitch: 1.375-24 (HUB/Bravo standard)
• Suppressor Compatibility: Most rifle suppressors with HUB/Bravo threading
• Wrench Flats: 1-7/16 inches
• Spanner Notches: 1.5 inches
• Added Length: 0.18 inches
• Recess Depth: 0.40" deeper than standard LPA
• Weight: 2.1 oz
• Market Position: Lightest recessed steel Plan-B HUB adapter
• Profile: Recessed
• Attachment/Removal: Quick (tool-free with Plan-B muzzle devices)
• Design Benefits: Shortened overall suppressor length, tighter handguard-to-suppressor gap
• Installation Tools: Compatible with 1-7/16" wrench or 1.5" spanner wrench
• Comparison: Shorter than standard LPA (Low Profile Adapter)
• Safety Requirements: Alignment rod verification required, bullet stabilization check required
• Fitment Note: Places muzzle devices 0.40" deeper - verify clearance before purchase
• Warranty Notice: Some suppressor manufacturers do not warranty products with aftermarket mounts - verify before use
• Liability: User assumes responsibility for proper use and alignment verification
• Applications: Rifle suppressors, compact builds, SBRs, carbines, precision rifles