The CMMG Resolute MK4 is a direct-impingement AR-platform rifle chambered in 6.5 Grendel. At 6.4 lbs unloaded, it's light enough to carry in the field without sacrificing the longer effective range that 6.5 Grendel offers over .223. The 16.1-inch barrel is 416 stainless steel with a Cerakote finish and a 1:8 twist rate — well-matched to the heavier bullets this caliber favors. Threading is 5/8 x 24 with a CMMG ZEROED muzzle brake installed, so swapping to a suppressor is straightforward. 
 

Key Specifications 

• Model: Resolute MK4 
• Manufacturer: CMMG 
• Caliber: 6.5 Grendel 
• Barrel Length: 16.1 inches 
• Capacity: 10 rounds 
• Weight: 6.4 lbs (unloaded) 
• Condition: New in Box 
• Finish Color: Black 
   
  The CMMG ZEROED charging handle and ambidextrous safety selector work equally well for left- and right-handed shooters. The direct-impingement operating system keeps the weight down and simplifies the gas system compared to piston alternatives. 6.5 Grendel magazines top out at 10 rounds in the standard configuration shipped with this rifle.

Owners of the CMMG Resolute MK4 in 6.5 Grendel highlight accuracy at distance as the main reason to choose this platform. The 6.5 Grendel cartridge's ballistics get credit for most of that, but users note that the stainless barrel and 1:8 twist live up to the caliber's potential. Build quality reviews are consistently positive — CMMG's fit and finish comes up often as a step above budget AR makers. The main friction points in discussions are price and ammo availability: 6.5 Grendel costs more per round and is harder to find at local stores than .223 or .308, which matters for high-volume shooters. Those who accept that tradeoff tend to be satisfied, especially hunters targeting medium to larger game at longer ranges where the cartridge earns its keep.