CMMG ZEROED Adjustable Gas Block – .750″, 20-Position Adjustment
The CMMG ZEROED Adjustable Gas Block provides 20-position gas adjustment for AR-platform barrels with a .750-inch gas block journal. Its detent adjustment system allows gas flow to be fine-tuned to accommodate differences in ammunition, operating conditions, and suppressed or unsuppressed configurations.
Constructed from 4140 steel and 17-4 stainless steel with a nitride finish, the ZEROED Adjustable Gas Block also features a user-serviceable design and sacrificial cleanout chamber to help manage carbon buildup.
CMMG ZEROED Adjustable Gas Block Specifications
- Manufacturer: CMMG
- Product: ZEROED Adjustable Low Profile Gas Block
- CMMG Product Number: 55DA31F
- Gas Block Size: .750″
- Inside Diameter: .750″
- Adjustment: 20-position detent adjustment
- Material: 4140 Steel / 17-4 Stainless Steel
- Finish: Nitride
- Type: Adjustable Gas Block
- Included: 6″ 3/32″ hex adjustment wrench and roll pin
20-Position Gas Adjustment
The ZEROED gas block uses a 20-position detent adjustment screw to control gas flow through the AR gas system.
This adjustability allows the gas system to be tuned for the firearm’s operating conditions rather than relying on a single fixed gas setting. Changes in ammunition, fouling, muzzle devices, environmental conditions, and suppressor use can all influence AR gas-system performance.
Designed for Suppressed and Unsuppressed Use
Adding or removing a suppressor can change gas pressure within an AR operating system. An adjustable gas block provides a way to compensate for those differences by changing the amount of gas delivered through the system.
CMMG specifically designed the ZEROED Adjustable Gas Block to allow users to tune their gas setting when moving between suppressed and unsuppressed configurations or when optimizing the system for a preferred ammunition load.
User-Serviceable Carbon Management
Carbon accumulation is an important consideration with adjustable gas components. CMMG incorporates a sacrificial cleanout chamber into the ZEROED design, providing excess carbon with an area to accumulate that remains accessible for cleaning.
The gas block is user-serviceable, allowing routine maintenance rather than treating the adjustment system as an inaccessible component.
.750″ Gas Block Compatibility
The CMMG ZEROED Adjustable Gas Block has a .750-inch inside diameter and is intended for barrels with a compatible .750″ gas block journal.
Always verify your barrel’s gas block journal diameter and component compatibility before purchase or installation.
Frequently Asked Questions
What size barrel does the CMMG ZEROED Adjustable Gas Block fit?
The ZEROED Adjustable Gas Block has a .750″ inside diameter and is designed for barrels with a compatible .750-inch gas block journal.
How many adjustment positions does the CMMG ZEROED gas block have?
CMMG uses a 20-position detent adjustment system that allows gas flow to be incrementally adjusted.
Can the CMMG ZEROED gas block be used with a suppressor?
CMMG specifically identifies suppressed shooting as one of the applications for the ZEROED Adjustable Gas Block. Suppressor use can alter gas-system pressure, and the adjustable gas block allows the system to be retuned for those operating conditions.
Can it also be used without a suppressor?
Yes. The ZEROED Adjustable Gas Block can also be used to fine-tune an AR gas system for unsuppressed operation and different ammunition or operating conditions.
What is the CMMG ZEROED Adjustable Gas Block made from?
CMMG lists the materials as 4140 steel and 17-4 stainless steel with a nitride finish.
Does the gas block include an adjustment wrench?
Yes. CMMG includes a 6-inch 3/32″ hex wrench for gas adjustment as well as a roll pin.
Is the CMMG ZEROED Adjustable Gas Block user-serviceable?
Yes. CMMG describes the ZEROED gas block as user-serviceable and incorporates a sacrificial cleanout chamber designed to provide an accessible location for excess carbon buildup.
Important Compatibility Notice
Confirm barrel gas block journal diameter and compatibility with all related components before installation. Gas-system requirements can vary depending on the firearm, barrel, ammunition, muzzle device, and other components. Follow CMMG’s current instructions and safety procedures when installing, adjusting, or servicing the ZEROED Adjustable Gas Block.
