CMMG Inc Gas Ring Helical MK3. These CMMG Original Gas Rings are machined from solid steel and are built to last. When used with CMMG Gas Ring Nuts and staking adapters (sold separately) they offer the classic look of an original gas ring. The design of CMMG Gas Rings makes them great for upgrading your CMMG bolt to a billet gas ring or for rebuilding an SR. In most cases you can reuse your original gas rings but if you need a custom look or have an existing firearm you can order a custom made gas ring from a trusted gunsmith or machine gunsmith. Specifications for CMMG Inc Gas Ring: Manufacturer: CMMG Condition: New Color: White Quantity: 1 Package Contents: CMMG Inc Gas Ring CMMG Inc 38BA498: Gas RingHelicalMK3