Griffin's MK2 9mm Brings Colt-Pattern Magazines to a Modern PCC
Griffin Armament's MK2 9mm is a 4.5-inch pistol-caliber carbine with a forged receiver set, fully ambidextrous controls, and a lower receiver that accepts Colt-pattern 9mm magazines without an adapter. The Firearm Blog ran a hands-on review of the gun on October 27, 2026. The reviewer paired the carbine with Griffin's Sportsman Ultralight HD suppressor and reported a crisp trigger break at four pounds. Griffin built the MK2 for shooters who want AR-style controls on a submachine-gun-style platform, and this review shows how well that design works in practice.
Key Details
The review centers on a specific configuration, and the numbers matter for anyone shopping this platform. The test gun carried these features:
- Barrel: 4.5 inches, paired with the Griffin Sportsman Ultralight HD suppressor under the handguard.
- Magazines: Metal Form Colt-pattern 9mm stick magazines, a true double-feed design. The test gun shipped with two 32-round magazines. Griffin also sells 10- and 20-round versions.
- Magazine pricing: $47.95 to $57.95 per magazine, according to the review.
- Feed system: A proprietary feed ramp made of 17-4 nitrided steel, secured by three Allen screws. The ejector and bolt catch extension is a single part, with no separate ejector adjustment.
- Receiver set: Forged, with ambidextrous bolt catch, magazine release, and selector. The charging handle is Griffin's SN-ACH Gen 2, designed for suppressor use.
- Trigger: Griffin's adjustable Kreiger Milazzo-style two-stage match trigger. The reviewer measured the second stage at a consistent four pounds on a Wheeler Trigger Pull Scale, with no overtravel.
- Grip: Griffin's A3 grip, with a moderate texture.
- Buffer and extension: A brass H2 buffer inside Griffin's six-position Maritime Receiver Extension.
- Fit: A 1/4-28 nylon-tipped tension screw sets the upper-to-lower fit. The reviewer's sample needed no adjustment.
The reviewer's complaints were small. He wanted a shorter, tapered right-side selector because his hand rides over the lever. He also called the trigger more than the carbine needs. The magazine well includes a flared opening, and machined shelves around both magazine releases help prevent accidental magazine drops. The takedown pins are dimpled to protect the finish during disassembly. The review also notes that the test pistol came with an SBA3 brace, though the excerpt the source gives stops before the brace discussion.
Background
Colt's original 9mm carbine magazine well used an insert held in place with roll pins. Shooters who wanted to run Colt-pattern magazines had to fit those inserts and tune the feed. Griffin's design cuts out the insert and sizes the lower receiver to accept Colt-pattern magazines natively. That change matters because it removes a fitting step and a common point of failure from the build.
Double-feed Colt-pattern magazines have long been the standard for submachine-gun-style carbines. Most pistol-caliber carbine owners know the trade-off: Glock-pattern magazines are cheaper and easier to find, but they feed from a single column and are less reliable with some carbine designs. The reviewer also noted that Colt-pattern magazines hold the bolt open after the last round, which Glock magazines do less reliably.
The regulatory backdrop has shifted too. In 2023, ATF tried to reclassify many braced pistols as short-barreled rifles, and federal courts pushed back on that approach. Separately, the 2025 federal budget law reduced the $200 NFA tax on suppressors to zero, effective January 1, 2026. A suppressor-ready carbine like the MK2 now carries a lower tax burden than it did a few years ago.
Why It Matters for Gun Owners
This carbine matters most to owners who already run Colt-pattern magazines or who want a PCC built to suppressor standards. The native magazine well removes the need for an adapter, which means fewer parts between the magazine and the chamber. Owners who run suppressors should look at the SN-ACH Gen 2 charging handle, since a suppressor-optimized handle reduces the chance of getting a hand burned on a hot can. The ambidextrous controls help left-handed shooters and anyone who clears malfunctions quickly.
The cost is the real barrier. Two magazines at $47.95 to $57.95 each add up fast once you buy a full set of 10-, 20-, and 32-round magazines. Glock-pattern owners will need to budget for a new magazine supply if they switch platforms. Buyers who plan to run the carbine with a suppressor should check their state's rules on suppressor ownership and transport before buying. Watch the NFA paperwork timeline, too, since tax-free status does not change the federal registration requirement for suppressors and short-barreled rifles.
DownRange Analysis
The MK2 9mm is a serious build, and the design choices are sound. A forged receiver with mil-spec-style controls is a practical choice, and the native Colt-pattern well is a real engineering improvement over the roll-pinned insert. Post-Bruen, the Second Amendment question is simpler for pistol-caliber carbines than for many other firearms. Courts have generally protected the right to keep and bear common arms like these. Regulatory fights over braces and short-barreled rifles are a different matter, and buyers should track them.
What should a gun owner do right now? If you already own Colt-pattern magazines, the MK2 is worth a look. If you run a Glock-pattern PCC, weigh the magazine cost before switching. If you plan to run a suppressor, confirm your NFA paperwork and your state's rules before you buy. Check the source review for full specs and the complete brace discussion.
