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CMMG
Overview
The CMMG AR-15 8.2" 300 Blackout MR Barrel is designed for those looking to maximize the performance of their compact builds. With a medium profile and a pistol-length gas system, this barrel offers a balance of stability and maneuverability, making it ideal for close-quarters applications. Its 1:7 twist rate helps stabilize a wide range of bullet weights for enhanced accuracy. This barrel is frequently found in builds specifically configured for the 300 Blackout caliber, catering to shooters who prioritize versatility and effectiveness in short-range engagements.
CMMG AR15 8.2" 300BLK Mr Barrel ranked #23 of the 298 barrels builders added on GunPartPicker in August 2026. Builders have been adding it to their builds on GunPartPicker since February 2026. All time, it ranks #27 of the 814 barrels builders have added. Builds with this barrel are nearly all chambered in 300 Blackout, nearly all on pistol-length gas, and nearly all AR-15.
It was in stock most days in August 2026, but today 2 of the 9 retailers we track have it in stock. It dipped to $132.54 at BattleHawk Armory for a stretch in August 2026, under its usual $144.99 to $153.99, so sales do come around. Buying today, the lowest price is $144.99 at GritR Sports, above August's low of $132.54, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 35 retailers
We ranked every barrel by how often it shows up in real builds on GunPartPicker.
Read the guide: AR-15 Barrel Length & Brand Report →Check it against the live catalog:
The part most often added in each category by the 19 builds that include this one
Aero Precision M4E1 Threaded Stripped AR-15 Upper - No Forward Assist - Anodized Black
Aero Precision AR-15 Breach Charging Handle Ambidextrous Small Levers
Midwest Industries Suppressor Series M-LOK AR-15 Handguard - 10.5"
Aero Precision AR-15 5.56 BCG W/C158 Bolt - Aero Logo - Phosphate
Silencerco AR-15 Billet Lower Receiver
Aero Precision Gas Tube, Pistol Length - Stainless Steel
Builds in the community that include the Cmmg Ar15 8.2" 300blk Mr Barrel
| Build | Parts | Total |
|---|---|---|
 | 17 | $2108.59 |
 | 16 | $2809.40 |
| 7 | $946.34 |
 | 20 | $1912.56 |
 | 17 | $1543.65 |
1 global rating
Top reviews
CMMG 8.2 inch 300 BLK barrel cycles subsonic and supersonic 300 BLK from the same gas port. Chamber finish is clean. Standard 5/8x24 threading. Heats up quick as expected for short barrel suppressed shooting.
