The CMMG Resolute Mk4 in .300 Blackout (MPN 30A240A-MB) pairs a 14.5-inch barrel with the CMMG ZEROED SV brake pinned and welded in place, bringing the overall barrel length to a legal 16.1 inches without any NFA paperwork. CMMG built the rifle to be one of the most compact AR-15s that’s still legally a rifle, with the full range of supersonic and subsonic .300 Blackout loadings suiting it to both long-range and close-quarters use. It’s built on the carbine-length Mk4 platform with the full suite of ZEROED parts and the CMMG RipStock, and the EML15 handguard adds M-LOK slots at the 3, 6, 9, and 12 o’clock positions in place of a full-length Picatinny section to save weight. Among AR-platform rifles in the AR rifles category, the Resolute Mk4 favors shooters who want a compact, pinned-and-welded .300 Blackout rifle without stepping into SBR territory.

Key Specifications

• Chambered in .300 AAC Blackout, running both supersonic and subsonic loads.
• Features a 14.5-inch barrel, pinned and welded to a legal 16.1 inches.
• The muzzle device is the CMMG ZEROED SV brake, permanently attached.
• The handguard is a CMMG EML15 M-LOK design.
• Fitted with the CMMG RipStock.
• Finished in Midnight Bronze.
• Feeds from a detachable magazine with a 30-round capacity.
• Ships at approximately 8.4 pounds shipping weight.

Frequently Asked Questions

Why is the barrel pinned and welded? It permanently extends a 14.5-inch barrel to the legal 16-inch minimum, avoiding NFA registration as a rifle.

What finish does this rifle have? Midnight Bronze.

Does .300 Blackout work suppressed? Yes, the cartridge runs a full range of subsonic loads suited to suppressed use.

Buy the CMMG Resolute Mk4 .300 Blackout, Midnight Bronze

A compact, pinned-and-welded .300 Blackout rifle without stepping into SBR territory is exactly what the Resolute Mk4 delivers. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL.