CMMG115665469
CMMG MK3 6.5 Creedmoor Bolt Carrier Group$259.51
Availability: In Stock
The CMMG MK3 .308 Win black phosphate steel bolt carrier group is a complete, ready-to-run upper receiver component built for AR-platform .308 rifles. If you're assembling or upgrading a modern sporting rifle in this caliber, this drop-in carrier group handles the critical job of chambering, firing, and extracting—with no guesswork or additional fitting required. It's the kind of part you want to trust, especially in a rifle designed for serious shooting.
CMMG machines the carrier from 8620 steel with a protective black phosphate finish and chrome-lined interior for durability and corrosion resistance under sustained fire. The bolt itself is cut from 9310 hardened steel—a tough alloy that resists wear and stress—with a hardened S7 tool steel extractor. The firing pin is stainless steel, and the gas key arrives torqued to spec and staked properly so you don't have to second-guess those critical settings. The group includes the cam pin and firing pin retaining pin you'll need for assembly.
Note that this carrier lacks serrations for a forward assist, so confirm your upper receiver design before ordering. Otherwise, it's a proven, no-fuss component for hunters, competition shooters, and riflemen building or maintaining a reliable .308 AR platform rifle.
| Caliber | .308 Winchester |
| Carrier Material | 8620 Steel |
| Carrier Finish | Black Phosphate with Chrome Lining (interior) |
| Bolt Material | 9310 Hardened Steel |
| Extractor Material | S7 Tool Steel (hardened) |
| Firing Pin Material | Stainless Steel |
| Model | MK3 |
| Part Number | 38BA423 |
Yes, the CMMG MK3 is designed as a drop-in component for .308 AR-pattern rifles. However, note that it does not have serrations for a forward assist, so verify your upper receiver is compatible with a non-serrated carrier before purchasing.
You receive the complete carrier group with the bolt, firing pin, extractor, cam pin, and firing pin retaining pin. The gas key is already torqued to specification and staked, so no additional assembly of those critical components is needed.
The chrome lining on the inside of the carrier reduces friction, improves corrosion resistance, and extends the service life of the component, especially under heavy or sustained fire.
Both are high-quality alloys. The 8620 carrier steel is durable and takes a good finish; the 9310 bolt steel is specifically hardened to withstand the extreme stresses of chambering and firing. Together, they provide the strength and longevity you need in a rifle that works hard.
SKU: 115816843 • Width: 1.8in • Height: 1.8in • Depth: 9in • Weight: 1.29oz
Availability: In Stock
The CMMG MK3 .308 Win black phosphate steel bolt carrier group is a complete, ready-to-run upper receiver component built for AR-platform .308 rifles. If you're assembling or upgrading a modern sporting rifle in this caliber, this drop-in carrier group handles the critical job of chambering, firing, and extracting—with no guesswork or additional fitting required. It's the kind of part you want to trust, especially in a rifle designed for serious shooting.
CMMG machines the carrier from 8620 steel with a protective black phosphate finish and chrome-lined interior for durability and corrosion resistance under sustained fire. The bolt itself is cut from 9310 hardened steel—a tough alloy that resists wear and stress—with a hardened S7 tool steel extractor. The firing pin is stainless steel, and the gas key arrives torqued to spec and staked properly so you don't have to second-guess those critical settings. The group includes the cam pin and firing pin retaining pin you'll need for assembly.
Note that this carrier lacks serrations for a forward assist, so confirm your upper receiver design before ordering. Otherwise, it's a proven, no-fuss component for hunters, competition shooters, and riflemen building or maintaining a reliable .308 AR platform rifle.
| Caliber | .308 Winchester |
| Carrier Material | 8620 Steel |
| Carrier Finish | Black Phosphate with Chrome Lining (interior) |
| Bolt Material | 9310 Hardened Steel |
| Extractor Material | S7 Tool Steel (hardened) |
| Firing Pin Material | Stainless Steel |
| Model | MK3 |
| Part Number | 38BA423 |
Yes, the CMMG MK3 is designed as a drop-in component for .308 AR-pattern rifles. However, note that it does not have serrations for a forward assist, so verify your upper receiver is compatible with a non-serrated carrier before purchasing.
You receive the complete carrier group with the bolt, firing pin, extractor, cam pin, and firing pin retaining pin. The gas key is already torqued to specification and staked, so no additional assembly of those critical components is needed.
The chrome lining on the inside of the carrier reduces friction, improves corrosion resistance, and extends the service life of the component, especially under heavy or sustained fire.
Both are high-quality alloys. The 8620 carrier steel is durable and takes a good finish; the 9310 bolt steel is specifically hardened to withstand the extreme stresses of chambering and firing. Together, they provide the strength and longevity you need in a rifle that works hard.
SKU: 115816843 • Width: 1.8in • Height: 1.8in • Depth: 9in • Weight: 1.29oz