Comstock Armory 9mm Quick Detach Recessed Plan-B HUB Suppressor Mounting Kit

Comstock Armory 9mm Quick Detach Recessed Plan-B HUB Suppressor Mounting Kit

The Comstock Armory 9mm Quick Detach Recessed Plan-B HUB Suppressor Mounting Kit combines two 1/2x28 recessed 9mm micro brakes with one steel RPA HUB adapter. The larger brake bore makes this a flexible mounting package for compatible 5.56, 9mm and .350 Legend firearms, with a common Plan-B interface and a compact recessed profile.

This kit contains everything you need in mounting hardware to mount your compatible HUB suppressor to multiple 1/2x28-threaded 5.56/9mm/.350 Legend/.36-class firearms while keeping an ultra-tight, low-profile mounting system. For .36-class applications, the included brakes are limited to bullets no larger than .357/9mm. The pair of brakes equips two compatible firearms.

Shop this Comstock Armory 9mm mounting kit at BattleHawk Armory for a compact Plan-B setup across two compatible firearms.

Kit Contains

• 2x Comstock Armory Recessed Micro Plan-B Muzzle Brake, 1/2x28, 9mm, Black Nitride - SKU: MBM-12-9-R - UPC: 850069580391
• 1x Comstock Armory RPA HUB Recessed Plan-B Suppressor Adapter, Stainless Steel - SKU: RPA-B-SS - UPC: 850069580285

The package contains three mounting components: two muzzle brakes and one suppressor adapter. Firearms and a suppressor are not included.

Recessed Plan-B HUB Mounting

The RPA-B-SS adapter connects a compatible 1.375-24 HUB/Bravo suppressor to the included Plan-B-pattern muzzle devices. Its recessed profile positions the muzzle device 0.40 inch deeper than the standard Comstock LPA, shortening the assembled mounting configuration and helping create a tighter handguard-to-suppressor gap. The adapter itself adds 0.18 inch of length and weighs 2.1 ounces.

One adapter serves the compatible suppressor while the two brakes provide matching attachment points on two firearms. Quick-detach convenience and the recessed profile work together for a compact system. Actual spacing depends on the firearm, muzzle device and suppressor combination.

Two 1/2x28 Brakes with a .357/9mm Bullet Limit

Each MBM-12-9-R recessed micro brake uses 1/2x28 barrel threads and accepts bullets up to .357/9mm. Each measures 1.25 inches overall, adds 0.42 inch beyond the muzzle and weighs 1.4 ounces. That bore range accommodates the listed smaller-caliber applications when the firearm and suppressor meet the complete fitment requirements. A 9mm brake does not make a smaller-bore suppressor suitable for 9mm.

The recessed micro brake design reduces recoil and acts as a sacrificial surface ahead of the suppressor blast baffle. Its rotationally symmetric geometry does not require timing with shims. Limited forward protrusion is useful with the recessed adapter, while the complete combination still requires adequate internal clearance.

17-4 PH Stainless Steel and Black Nitride

Both muzzle brakes and the RPA adapter use 17-4 PH stainless steel with a black nitride finish. The kit pairs professional-grade steel components with a consistent black appearance. The included adapter is the steel RPA-B-SS configuration, with the same material and finish family as the recessed micro brakes.

Compatibility and Clearance

Both firearms must have compatible 1/2x28 muzzle threads and a barrel diameter of 0.750 inch or less where the recessed brake overlaps the barrel. The .36-class description does not cover bullets larger than .357/9mm. The suppressor must have a compatible 1.375-24 HUB/Bravo rear interface, sufficient bore clearance and the correct cartridge and barrel-length rating. Confirm blast-chamber, handguard and firearm-specific mounting compatibility.

Product Specifications

• Component manufacturer: Comstock Armory
• Configuration: 9mm Recessed Plan-B HUB Mounting Kit
• Included hardware: Two recessed micro muzzle brakes and one steel RPA adapter
• Barrel threads: 1/2x28 on both muzzle brakes
• Caliber / bore limits: 5.56, 9mm, .350 Legend and suitable .36-class applications; maximum bullet diameter .357/9mm
• Suppressor rear interface: 1.375-24 HUB/Bravo
• Muzzle-device interface: Plan-B pattern
• Material / finish: 17-4 PH stainless steel / black nitride
• Brake length: 1.25 inches overall; 0.42 inch added beyond the muzzle
• RPA profile: 0.18 inch added adapter length; muzzle device sits 0.40 inch deeper than with the standard LPA
• Maximum barrel diameter at brake recess: 0.750 inch
• Component weights: 1.4 oz per brake; 2.1 oz adapter

Frequently Asked Questions

Does the .36-class description include every .36-caliber cartridge?

No. The MBM-12-9-R is limited to bullets up to .357/9mm. Both the bullet diameter and the suppressor's cartridge rating must be suitable. A cartridge name or shared thread pitch alone does not establish compatibility.

Does this package include two suppressor adapters?

No. It includes two muzzle brakes and one RPA-B-SS adapter. The package supplies two firearm-side mounting points for one compatible suppressor.

Does HUB threading alone guarantee fit?

No. Matching rear threads are one requirement. The recessed mounting position also requires suitable blast-chamber depth, handguard clearance, barrel dimensions and caliber compatibility.

Order the Comstock Armory 9mm Quick Detach Recessed Plan-B HUB Suppressor Mounting Kit from BattleHawk Armory. Bring matching recessed components together in one specialized package for your two compatible firearms.