Battle of the AR-9 | Which One Shoots Best?

Defining the AR9 Platform and Operating Systems

The hosts open at Take Aim Training Range in South Carolina and outline what qualifies as an AR9. They describe it as essentially a scaled-down M16 or AR-15 pattern gun chambered in pistol calibers like 9mm, .40, .45, 10mm, or .357, typically using smaller carbine magazines. An AR9 is said to retain the traditional AR buffer tube and buffer system, with gas or blowback operation cycling the bolt and spring in a familiar way. They distinguish AR-15, AR-10, and AR9 platforms mainly by caliber and operating system, noting that most AR-pattern guns share the same basic buffer-driven cycle of operation, while some newer designs deviate from that pattern.

CMMG Dissent Mk4 and Its Radial Delayed System

The first carbine examined is the CMMG Dissent, referred to as a Mark 4, chambered in 9mm. It uses CMMG’s RDB, or radial delayed blowback system, which mechanically locks the bolt, vents gas and energy, then unlocks to cycle the next round. The lower resembles a standard M4 lower, but the magazines are unique: they fit into a standard AR-15 magwell yet internally house 9mm cartridges. This allows use of existing AR-15 lowers and gear while running 9mm with specialized mags. The hosts emphasize that the upper can be placed on most M4-style lowers, making it a flexible option for those with existing AR setups who want to shoot 9mm without changing their lower receiver.

Daniel Defense PCC and Hydraulic Buffer Design

Next up is the Daniel Defense PCC, a 9mm direct blowback gun. The hosts explain that in a simple blowback system, the firing pin ignites the cartridge and the resulting pressure drives the bolt rearward without a gas system. Daniel Defense adds a hydraulic buffer in the receiver extension to slow the bolt and reduce felt recoil. The carbine feeds from CZ Scorpion magazines, which are noted as highly reliable and commonly ranked alongside Glock and Colt stick magazines for PCC use. On the range, the Daniel Defense PCC is expected to feel softer than a typical straight blowback due to the hydraulic buffer, while still maintaining the straightforward reliability associated with blowback-operated 9mm carbines.

CMMG Banshee and Aero Precision EPC9 Range Impressions

The CMMG Banshee in 9mm is introduced as another radial delayed blowback platform, this time using Glock magazines. The bolt head has angled cuts that lock briefly, allowing gas pressure to drop before the bolt moves rearward, slowing the bolt speed and reducing felt recoil. A short barrel and a hand stop are highlighted as important for keeping the support hand safely behind the muzzle. The Aero Precision EPC9 is then discussed as a more traditional direct blowback AR9 that also uses Glock magazines and a longer barrel. On the range, the EPC9 is described as running very “healthy,” with noticeable recoil compared to the softer delayed systems, but praised for reliability and straightforward operation typical of Aero Precision builds.

Griffin Armament AR9, Colt Stick Mags, and Suppressed Shooting

Attention shifts to a Griffin Armament Mark 2 AR9-style carbine equipped with a suppressor for an SD-style appearance. It uses a direct blowback operating system and feeds from Colt stick magazines, which are described as the original AR9 magazine pattern and still considered a solid, reliable option. The buffer system in these blowback guns is notably heavy, often around an H4 weight, to slow the bolt’s violent rearward movement even though the caliber is only 9mm. On the range, the shooter notes that even with the suppressor attached, the gun clearly feels like a direct blowback platform. The trigger is adjustable and set to a light pull for this session, and the overall setup is presented as a classic Colt-mag AR9 configuration with a strong, distinctive feel.

Upgrading Blowback AR9s and Roller Delayed Prototypes

In the closing segment, the hosts discuss ways to improve the shooting characteristics of direct blowback AR9s like the Aero Precision and Griffin Armament builds. They mention aftermarket buffer systems from companies such as Maxim Defense and JP Enterprises that can add hydraulic or roller delayed characteristics to a standard blowback gun, bringing it closer to the smooth impulse associated with designs like the MP5 without fully replicating it. These buffer upgrades can be installed in existing AR9 platforms to reduce recoil and bolt speed. The video also briefly shows a new roller delayed prototype from Matador Arms, noting its clean ejection pattern and distinct feel. The hosts emphasize that magazines are often the root cause of malfunctions and should be checked before blaming the firearm itself.