Diamondback DB-15 Pistol .300 Blackout 10in OD Green SBA3
Pros & cons
What works
- 10-inch 4140 CMV nitride-finished barrel—optimal for .300 Blackout powder burn
- Weighs 5.7 lb empty—2.1 lb lighter than a 16-inch AR-15 rifle
- Includes $135 worth of accessories (SBA3 brace + Magpul PMAG)
- 26-inch collapsed length—fits in standard 28-inch rifle cases
Trade-offs
- No sights included—adds minimum $150 for quality iron sights or red dot
- .300 Blackout ammo costs $0.85/round vs $0.45 for 5.56mm—nearly double operating cost
- Pistol configuration requires careful legal awareness—not ideal for novice buyers
- Direct impingement system runs dirtier than piston-driven alternatives when suppressed
Video review
Expert review
Specs at a glance
About this product
The Diamondback DB-15 Pistol in .300 Blackout is a purpose-built 10-inch barreled AR-platform firearm configured as a pistol under current ATF guidelines, designed to maximize ballistic performance from short barrels while maintaining compatibility with standard AR-15 parts. This platform exists in a tightly regulated space between handguns and short-barreled rifles (SBRs), defined by its sub-16" barrel and stabilizing brace instead of a traditional rifle stock. As a Category D specialist here at Ironclad Armory, I evaluate these platforms against two benchmarks: mechanical reliability for defensive use and clarity of current legal configuration.
What is the Diamondback DB-15 Pistol used for?
This pistol is designed for compact defensive scenarios, vehicle-based carry, and suppressed shooting where the .300 Blackout cartridge's high subsonic energy is an advantage over shorter 5.56mm barrels. The 10-inch barrel is the sweet spot for .300 Blackout ballistics, allowing the cartridge to achieve full powder burn and maintain terminal effect out to around 200 yards—a distinct capability gap compared to a standard 9mm pistol-caliber carbine. This configuration makes it a logical choice for a home defense primary where maneuverability in tight spaces is critical, or as a dedicated truck/UTV firearm where its 26-inch collapsed length fits easily behind a seat.
How does the Diamondback DB-15 Pistol compare to a PSA 10.5" .300 Blackout pistol?
The Diamondback DB-15 offers superior barrel composition and finish over the base-model Palmetto State Armory 10.5" .300 Blackout pistol, which typically ships with a 4150 CMV barrel but lacks the Diamondback's black nitride finish and heavier profile. The Diamondback's 4140 Chrome-Moly Vanadium barrel with nitride treatment provides better corrosion resistance and easier cleaning, especially important for suppressed use where carbon fouling is accelerated. However, the PSA is often $150-200 less expensive, making the Diamondback the choice for shooters prioritizing barrel longevity over initial cost savings.
What does it weigh and what are the dimensions?
This pistol weighs approximately 5.7 pounds unloaded and measures 26 inches from muzzle to the end of the collapsed SBA3 brace, extending to 28.5 inches for proper cheek weld. The 9-inch M-LOK handguard provides 28 uninterrupted inches of accessory rail space across the 3-, 6-, and 9-o'clock positions, enough to mount a compact weapon light like the Streamlight TLR-1 HL (3.4 ounces) and a handstop without interfering with the shooter's grip. For comparison, a traditional 16-inch AR-15 rifle like our Stevens 334 in .308 is at least 34 inches overall and weighs closer to 7.5 pounds.
Who is this NOT for?
This pistol is not for first-time AR platform buyers or those seeking a low-cost plinking rifle, as .300 Blackout ammunition costs roughly $0.85 per round for supersonic loads versus $0.45 for 5.56mm. It's also a poor choice for buyers who are unwilling to maintain clear documentation of its pistol configuration—retaining the original brace and understanding applicable state laws regarding magazine capacity is non-negotiable. Additionally, hunters looking for a dedicated lightweight woods rifle would be better served by our Stevens 334 in .243 Win which offers superior ballistic energy past 150 yards.
What's in the box?
The factory package includes the complete DB-15 pistol, one SB Tactical SBA3 adjustable arm brace, one Magpul Gen M3 30-round PMAG, and all required compliance paperwork. Notably absent is any form of optic or iron sights—you'll need to budget an additional $150-400 for a quality red dot like the Sig Sauer Romeo5 or Holosun 403R. The package weight shipped is approximately 11.5 pounds in a 36x12x8 inch cardboard box, which typically requires an adult signature upon delivery per our carrier agreements.
Is the Diamondback DB-15 Pistol worth it at $739.99?
At $739.99, this pistol represents good value within the $650-$900 market segment for complete .300 Blackout AR pistols, landing squarely in the mid-tier for components and finish quality. The inclusion of the $120 SB Tactical SBA3 brace and the $15 Magpul PMAG means the actual firearm cost is closer to $605, comparable to many basic 5.56mm rifles. For shooters specifically seeking a suppressed .300 Blackout platform, this configuration saves approximately $200 in parts and gunsmithing fees compared to converting a 16-inch rifle, making the price justifiable for that specific use case.
Key attributes
| upc | 810035754416 |
| manufacturer | Diamondback Firearms |
| manufacturer part number | DB1916B101 |
| action | Semi-Auto |
| atf type | Pistol |
| barrel length | 10" |
| caliber/gauge | .300 AAC Blackout |
| capacity | 30 + 1 |
| length | 26 |
| magazine included | 1 x 30-Round |
| model | DB15 |
| number of magazines | 1 30rd. PMAG |
| package height | 9.0 |
| package width | 3.5 |
| product type | Semi-Auto Pistol |
| safety | Thumb |
| shipping weight | 7.3 |
| sights | No Sights |
Frequently asked questions
- Is it compatible with standard AR-15 parts?
- Yes, the DB-15 uses mil-spec AR-15 components throughout, meaning any standard AR-15 bolt carrier group, charging handle, pistol grip, or trigger will drop in without modification. The 9-inch handguard uses a standard barrel nut interface compatible with most aftermarket rails measuring 9.5 inches or less.
- Does this work with a .300 Blackout suppressor?
- Absolutely—the 10-inch heavy barrel features a 5/8x24 threaded muzzle ready for any .30 caliber suppressor with that thread pattern. I recommend running it with a 7-8 inch suppressor like the SilencerCo Omega 300 or Dead Air Nomad-30 to keep overall length under 20 inches when configured for home defense.
- Can I use 5.56mm NATO ammunition in this firearm?
- No—this pistol is chambered exclusively for .300 AAC Blackout. Attempting to fire 5.56mm NATO rounds will result in a catastrophic failure due to chamber dimension mismatch. Always verify cartridge headstamp before loading any magazine.
- How many rounds does the included magazine hold?
- The package includes one Magpul Gen M3 PMAG with a 30-round capacity. These magazines are compatible with all .300 Blackout ammunition types including subsonic, supersonic, and specialized defensive loads like the Barnes 110gr Tac-TX.
- What's the shipping time to Texas?
- Firearms ship via UPS 2-Day Air to your selected FFL dealer, typically departing our warehouse within 2 business days after all compliance documentation is verified. Total transit time to Texas is usually 4-6 business days from order placement.
- Does Ironclad Armory handle the FFL transfer paperwork?
- We initiate all required ATF Form 4473 documentation electronically with your chosen FFL dealer, but the actual transfer must be completed in person with valid photo ID. We maintain a network of over 3,000 participating dealers nationwide who charge between $25-$50 for the transfer service.