Haven't seen or heard anything from Mossberg, but these barrels showed up on AIM Surplus...
Mossberg 16" .300 BLACKOUT AR Barrel
Not sure if they plan on a .300 BLK MMR, but these barrels showing up certainly point to the possibility...
Mossberg 16" .300 BLACKOUT AR Barrel
New Mossberg 16" .300 BLACKOUT caliber barrels for AR type Rifles. These high quality barrels feature a complete inside and out Melonite coating, 1:7 twist and M4 feed ramps.
Specifications:
- .300 BLACKOUT Caliber
- 1:7 Twist Rate
- M4 Feed Ramps
- Carbine length gas hole
- Uses .750 gas block (not included)
- Muzzle thread pitch 5/8x24
Not sure if they plan on a .300 BLK MMR, but these barrels showing up certainly point to the possibility...