AR15 12.5" 300BLK Mr Barrel
$181.99 at Ammunition Depot · 6 stores
In stock
Best price
$153.99at Ammunition Depot
In stock checked Oct 21, 2026
Where to buy
| Store | Price | Availability | Buy | Add to build |
|---|---|---|---|---|
| Ammunition Depot Best price | $153.99checked Oct 21, 2026 | In stock | Buy at Ammunition Depot | |
| GunMag Warehouse | $164.99checked Oct 21, 2026 | In stock | Buy at GunMag Warehouse | |
| OpticsPlanet | $172.49Salechecked Oct 21, 2026 | In stock | Buy at OpticsPlanet | |
| Palmetto State Armory | $168.99checked Oct 21, 2026 | Check store | Buy at Palmetto State Armory | |
| CMMG | $174.95checked Oct 21, 2026 | Check store | Buy at CMMG | |
| Brownells | $190.77checked Oct 21, 2026 | Out of stock | Buy at Brownells |
Prices and availability change often, so confirm on the store's site before you buy. We may earn a commission from these links.
Price history
Lowest in-stock price in the last 30 days: $153.99 at Ammunition Depot. Dashed line = out of stock. Tracking since Sep 28, 2026.
Show the prices as a table
| Store | Latest | Lowest | Highest |
|---|---|---|---|
| Ammunition Depot | $153.99 | $153.99 | $153.99 |
| Brownells | $190.77 | $190.77 | $190.77 |
| CMMG | $174.95 | $174.95 | $174.95 |
| GunMag Warehouse | $164.99 | $164.99 | $164.99 |
| OpticsPlanet | $172.49 | $169.99 | $172.49 |
| Palmetto State Armory | $168.99 | $168.99 | $168.99 |
Since Sep 28, 2026.
About this part
The AR15 8.2" 300BLK Mr Barrel is an 8.2" 300 Blackout barrel from CMMG. It's sold by 6 stores (3 in stock), from $153.99 to $190.77. The lowest in-stock price in the last 30 days was $153.99 at Ammunition Depot.
Fits and works with
- Caliber
- 300 Blackout · Shop matching ammo
- Bolt
- Standard AR-15 (5.56 / 300 BLK / .350 Legend) · Bolt carrier groups
- Barrel length
- 8.2" · Handguards
Specifications
- Manufacturer
- CMMG
- Color
- Black
- Platform
- AR-15
- Caliber
- 300 Blackout
- Barrel length
- 8.2"
From the manufacturer
Direct replacement for the standard .223/5.56mm barrel converts your AR-15 to the high-performance 300 AAC Blackout (300BLK) cartridge. The 300 AAC lets you upgrade your rifle to 7.62 x 39 ballistics, while retaining the standard AR-15/M16 bolt, carrier, and magazine at its full capacity, with no additional modifications. 1-7" rifling accepts bullet weights from 110 gr to 220 gr, and 5/8"-24 muzzle threads accept popular AR-.308 flash suppressors and muzzle brakes. Three models available, 16", 12.5" and 8.2" long and treated inside and out with CMMG's "Wasp" nitriding process for outstanding resistance to wear and corrosion. 16" barr Mfg: Cmmg SPECS: Hardened 4140 chrome-moly steel, Wasp nitride finish, matte black .750" O.D. at gas port.5/8-24 muzzle threads.
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