JMAC RRD-4C SLIM AK Muzzle Brake Review

When it comes to AK rifles, I’m a born-again traditionalist. I started out only wanting mil-spec, period-correct AK rifles, but gradually decked out a few of my Kalashnikovs in modern furniture and optics. While I initially didn’t love the aesthetics of these attachments, they offered such better performance over mil-spec guns, that I was eventually won over.

One such product is the JMAC Custom’s RRD-4C “SLIM” 14mm LH muzzle brake. Maybe it should be called a break, as it breaks your ears with how loud, and breaks your eyes with how bright it is. But the RRD-4C doesn’t just make your gun look and sound more intense, it obliterates any recoil generated by the 7.62x39mm cartridge.

Compact, attractive and effective, the RRD-4C is an excellent replacement for the slant cut comp found on Mil-Spec guns.

RRD-4C Design

The RRD-4C’s design is as simple as it is effective; the four chambers vent increasingly larger amounts of escaping gas to reduce the horizontal intensity of the recoil impulse.

Built from military-grade 17-4PH stainless steel, the JMAC RRD-4C Slim is only 2.1in long, 8.85in wide, and only weighs 1.8 ounces. The brake has a .360-in. bore, making it safe for use with 5.56, 5.45, and 7.62x39mm. While it might function fine with .308 or 7.62x54r VEPRs, JMAC doesn’t recommend it.

When you want to shatter darkness and cut all recoil from an AKM, accept no substitute.

The top of the brake features an indexing slot to allow the brake to be positioned perfectly in line with your AK’s sight tower. This is good, and seemingly common sense, but I’ve personally seen a few high-dollar AK muzzle devices that lacked this indexing slot. I would argue it would be very hard to defend the lack of an indexing slot for any reason other than reducing machining costs.

Interestingly enough, the RRD-4C isn’t just a brake, but also a compensator. While the original version was simply a brake—featuring only horizontal ports to redirect gas, the “C” variant also incorporates vertical cuts to compensate for muzzle rise.

The result is a spectacularly effective muzzle device.


For testing, the RRD-4C was installed on a full-sized RAS-47 AKM clone, an SBR’d Draco and a Polish Lynx AK pistol, and the results were incredibly impressive.

On both short-barreled AK variants, the RRD-4C took every ounce of kick out of the little blasters and instantly converted it into blasty mayhem. Side note, don’t use this brake for night shooting if you want to have any semblance of your natural night vision left after pulling the trigger—It’s like a miniature atom bomb detonating at the end of your muzzle.

The RRD-4C not only works great, but it also looks fantastic on this SBR’d Draco.

While the muzzle blast on the full-sized RAS wasn’t substantially increased, the sound of the shots themselves certainly was. So much so, that while wearing both molded earplugs and electronic ear muffs, the gun still left a slight ringing in my ears. Though this is probably more due to existing tinnitus than anything caused by the brake.

Overall, JMAC’s slim version of their AK muzzle brake does exactly what it set out to do: tame recoil. Shooters looking to improve their splits, or simply get their gun back on target faster should take a very serious look at JMAC’s RRD-4C Slim.

Jim is a freelance writer for dozens of firearm publications, the host of the YouTube channel Burst Review and the youngest author to write a cover story for Shotgun News in its 86-years of operation. Jim loves anything that goes, ‘boom’ but particularly enjoys military firearms from the Cold War and WW2. When he’s not slinging lead downrange he can be round hiking in the mountains with his wife Kim and their vicious attack dog, Peanut.

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