Diamondback DBX 5.7×28 8in 30+1 Black Strike Brace
Video review
Expert review
About this product
The Ironclad Armory Diamondback DBX 5.7×28 8in 30+1 Black Strike Brace is a purpose-built, compact firearm pistol that delivers high-capacity performance in a modular package for shooters prioritizing adaptability and compliance. Built on forged 7075 T-6 aluminum, it centers on the 5.7x28mm cartridge—a round that bridges handgun and rifle ballistics—and is configured here with an 8-inch barrel, a folding brace for compact transport, and a 30-round magazine. This platform is engineered for shooters who understand that lightweight construction and modern ergonomics require intentional design choices, not marketing gimmicks.
What is the DBX 5.7×28 used for?
The DBX is primarily a compact, high-capacity range pistol and defensive tool optimized for environments where maneuverability and magazine depth are priorities. Its 8-inch barrel and folding brace create an overall length of just 21.5 inches when collapsed, making it viable for vehicle carry or tight-quarters use where a full-length rifle would be impractical. The 5.7x28mm cartridge offers flat trajectory and low recoil compared to traditional pistol calibers, which translates to faster follow-up shots and improved accuracy at extended handgun distances, typically out to 100 yards with proper optics.
How does the DBX compare to the PSA Rock 5.7?
The DBX platform is mechanically superior to the PSA Rock 5.7 for shooters prioritizing modularity and suppressor readiness, but the Rock wins on magazine cost and ergonomic familiarity. The DBX uses a dual gas piston system housed within its aluminum handguard, which is more complex but runs cleaner and cooler during sustained fire than the Rock's direct blowback design. More critically, the DBX's 1/2x28 threaded barrel is suppressor-ready from the factory, whereas the Rock requires an aftermarket adapter; for builders looking to add a can, the DBX saves approximately $80-120 in parts and gunsmithing.
What does it weigh and what are the dimensions?
The DBX weighs 4.85 pounds unloaded, which is 1.3 pounds lighter than a typical AR-pattern pistol chambered in 5.56 NATO, largely due to its extensive use of aluminum. Its overall length measures 26.75 inches with the Strike brace deployed and collapses to 21.5 inches for storage—a reduction of over 5 inches that significantly improves portability. The M-LOK handguard provides 7.25 inches of accessory rail real estate, enough to mount a compact weapon light, a handstop, and a pressure pad without crowding the shooter's support hand.
Who is this NOT for?
This configuration is not for budget-conscious shooters or those unfamiliar with NFA regulations surrounding pistol braces and short-barreled rifles. At $1,167.99, the initial investment is substantial, and 5.7x28mm ammunition averages 45-55 cents per round—nearly double the cost of 9mm. More critically, the inclusion of a folding brace creates a regulatory gray area that requires owners to stay current on ATF rulings; if you're not prepared to monitor compliance updates, a traditional stocked rifle like the Stevens 334 in .308 Win is a far simpler choice.
What's in the box?
You receive the DBX pistol with the Strike FSA dual-folding brace installed, one 30-round metal magazine, a Magpul MOE K grip, and a basic owner's manual—no optic, sling, or cleaning kit is included. The package lacks thread protectors or muzzle devices, so if you plan to shoot without a suppressor, you'll need to purchase a 1/2x28 flash hider or compensator separately, typically a $25-50 addition. For a more complete out-of-the-box experience, consider a platform like the Stevens 555 Sporting shotgun, which includes choke tubes and a hard case.
Is the DBX worth it at $1,167.99?
Yes, for shooters who specifically need the ballistic profile and magazine capacity of the 5.7x28mm round in a compact, suppressor-ready format, the DBX justifies its price through material selection and intelligent design. The forged 7075-T6 aluminum receiver is a military-spec component that will outlast stamped steel alternatives, and the factory-installed folding brace provides immediate utility without aftermarket modification. If your use case is general plinking or home defense within 25 yards, a 9mm PCC offers similar performance at half the ammunition cost, but for those leveraging the 5.7's unique capabilities, the DBX is a competent execution.
Specs at a glance
Pros & cons
What works
- Weighs 4.85 lb — 1.3 lb lighter than an equivalent 5.56 AR pistol
- Folds to 21.5 inches overall length — reduces storage footprint by 24%
- Forged 7075-T6 aluminum receiver — exceeds MIL-A-8625 spec for fatigue resistance
- 30+1 round capacity — 50% more onboard ammunition than standard 9mm pistols
Trade-offs
- Proprietary magazines cost $38 each — 3x the price of a PMAG
- No thread protector included — requires aftermarket purchase for safe unfiltered firing
- 5.7x28mm ammunition averages $0.52/round — unsustainable for high-volume training
Key attributes
| upc | 810035756564 |
| manufacturer | Diamondback Firearms |
| manufacturer part number | DB1680L001 |
| action | Semi-Auto |
| barrel length | 8" |
| atf type | Pistol |
| caliber/gauge | 5.7 x 28 mm |
| capacity | 30 + 1 |
| number of magazines | 1 30rd. Magazine |
| package height | 3.5 |
| package width | 8.8 |
| product type | Semi-Auto Pistol |
| sights | No Sights |
| shipping weight | 5.35 |
Frequently asked questions
- Is it compatible with FN Five-seveN magazines?
- No, the DBX uses proprietary metal magazines designed specifically for this platform; FN Five-seveN polymer magazines will not seat or feed. Diamondback currently produces 20-round and 30-round variants, with aftermarket options from Promag offering a 50-round drum. Expect to pay $35-45 per magazine through authorized dealers like Brownells or Primary Arms.
- Does the threaded barrel accept a SilencerCo Osprey suppressor?
- Yes, the 1/2x28 thread pattern is standard for 5.7mm suppressors, including the SilencerCo Osprey 45, which can be configured with a 5.7mm end cap. You must use a fixed barrel spacer or Nielsen device rated for pistol-caliber use, which SilencerCo includes with the Osprey kit. Ensure the suppressor's outer diameter clears the M-LOK handguard, which requires at least 1.4 inches of internal clearance.
- Can the folding brace be replaced with a stock?
- Legally, replacing the brace with a stock requires filing a Form 1 with the ATF to create a Short-Barrel Rifle (SBR), which involves a $200 tax stamp and a wait time of 30-90 days. Mechanically, the DBX uses a standard AR-15 buffer tube interface, so any commercial carbine stock will fit after the tax stamp is approved. We recommend consulting an attorney specializing in firearms law before making any modification.
- How long does direct shipping take?
- Ironclad Armory processes orders within 1-2 business days and ships via FedEx 2Day to FFL dealers, with typical in-transit time of 3-5 business days depending on destination. All shipments require adult signature confirmation at the receiving FFL, so coordinate with your dealer before ordering. International orders and shipments to restrictive jurisdictions like California or New York are not accepted.