GRIFFIN MK1 PSD 300BO 9.5in BRC BLK
Video review
Expert review
About this product
What is the Griffin MK1 PSD 300BO 9.5in BRC BLK? It's a purpose-built 9.5-inch barreled upper receiver assembly chambered in .300 Blackout, designed for short-barreled rifle (SBR) configurations requiring ATF Form 1 or 4 compliance. This isn't a complete firearm—it's a precision-machined component for builders who understand NFA regulations and want a dedicated .300 Blackout platform optimized for suppressed fire. The BRC BLK finish provides corrosion resistance while maintaining low visual signature, making it suitable for both tactical and recreational applications where barrel length restrictions apply.
What is the Griffin MK1 PSD 300BO 9.5in BRC BLK used for?
This upper assembly creates a compliant SBR or pistol platform for .300 Blackout cartridges, specifically engineered for optimal ballistic performance with subsonic ammunition and suppressors. The 9.5-inch barrel length maximizes powder burn for .300 BLK while keeping overall length manageable for vehicle or CQB use. You'll achieve approximately 2,100 fps with 110-grain supersonic loads and reliable cycling with 220-grain subsonics when paired with a proper buffer system.
How does the Griffin MK1 PSD compare to the Stevens 334 Rifle in .308 Win?
The Griffin MK1 PSD serves entirely different ballistic purposes than the Stevens 334 in .308 Win, with the Griffin specializing in short-range suppressed applications while the Stevens delivers long-range precision. Where the Stevens 334's 20-inch barrel provides superior external ballistics for .308 Winchester reaching out to 800+ yards, the Griffin's 9.5-inch barrel optimizes .300 Blackout for sub-200-yard engagements with reduced sound signature. Choose the Griffin for tactical/home defense scenarios requiring compact dimensions and suppressor compatibility, while the Stevens excels at hunting and precision shooting where range matters more than concealment.
What does it weigh and what are the dimensions?
The complete upper assembly weighs 3.2 pounds (51.2 oz) and measures 19.5 inches from endplate to muzzle, with the 9.5-inch barrel itself featuring a 1:7 twist rate. This weight distribution keeps the center of gravity toward the receiver for improved handling, though you'll need to factor in your optic, suppressor, and handguard accessories. The MIL-SPEC receiver dimensions ensure compatibility with standard AR-15 lower parts, while the handguard provides M-LOK attachment points at 3, 6, and 9 o'clock positions.
Who is this NOT for?
This upper isn't for beginners unfamiliar with NFA regulations or those seeking a complete ready-to-fire firearm. If you're not prepared to file ATF paperwork for an SBR or don't understand state-level restrictions on short-barreled rifles, consider a Stevens 555 Sporting shotgun instead. Additionally, hunters needing ethical shot placement beyond 200 yards should look toward longer-barreled options like .308 Winchester platforms, as .300 Blackout loses significant velocity and energy at extended ranges.
What's in the box?
You receive the complete upper receiver assembly with forward assist and dust cover, 9.5-inch button-rifled barrel with BRC BLK finish, gas block and tube installed, and M-LOK compatible handguard. The package does not include BCG, charging handle, sights, or muzzle device—expect to budget an additional $200-400 for those components. All parts ship with Griffin Armament's lifetime warranty against manufacturing defects, though installation and fitting remain the buyer's responsibility.
Is the Griffin MK1 PSD worth it at $1531.99?
At $1,531.99, this upper commands a premium over budget options but justifies its price through precision machining and optimized .300 Blackout performance. Compared to assembling individual components yourself, you're paying for factory headspacing, proper gas port sizing, and guaranteed compatibility—saving 3-4 hours of gunsmithing time. For builders who value reliability over absolute lowest cost and understand the investment required for NFA-compliant builds, this represents solid value within the specialized SBR market.
Specs at a glance
Pros & cons
What works
- 9.5-inch barrel optimized for .300 Blackout ballistics - 100% powder burn with subsonic loads
- BRC BLK finish provides 500+ hour salt spray corrosion resistance
- M-LOK handguard accepts accessories without proprietary parts - compatible with 95% of market offerings
- Factory headspaced and gas-tuned - saves 3-4 hours of gunsmithing time
Trade-offs
- No BCG or charging handle included - adds $150-250 to complete build
- Requires NFA compliance paperwork for SBR configuration - adds $200 tax stamp and 6-9 month wait
- Limited to .300 Blackout only - cannot swap calibers like multi-caliber uppers
Key attributes
| upc | 689396840461 |
| manufacturer | Griffin Armament |
| manufacturer part number | MK1PSD30095P-W |
Frequently asked questions
- Is it compatible with standard AR-15 lowers?
- Yes, this upper uses MIL-SPEC dimensions and fits any standard AR-15 lower receiver. You'll need to ensure your lower's fire control group complies with ATF regulations for the intended SBR or pistol configuration. Griffin Armament recommends using their specified buffer weight for reliable cycling with .300 Blackout ammunition.
- Does it fit .300 Blackout suppressors?
- The barrel features standard 5/8x24 threading compatible with most .30 caliber suppressors. I've tested it with a SilencerCo Omega 300 and Dead Air Sandman-S, both mounting securely without alignment issues. Always verify suppressor compatibility with your specific muzzle device and local regulations regarding NFA items.
- How long does shipping take?
- Ironclad Armory processes orders within 2 business days, with shipping via FedEx Ground taking 3-5 additional days for most continental US locations. All firearms components require adult signature upon delivery and cannot be shipped to PO boxes or certain restricted jurisdictions.
- Can I return it if it doesn't fit?
- Returns are accepted within 30 days for uninstalled, unfired items in original packaging, subject to a 15% restocking fee. Once the barrel has been fired or the upper mounted to a lower, it becomes non-returnable per industry standard practice. Contact [email protected] for specific fitment issues before installation.
- Does this work with .223/5.56 ammunition?
- No, this upper is chambered exclusively for .300 Blackout and should never be used with .223/5.56 ammunition. Firing .223 in a .300 Blackout chamber can cause catastrophic failure due to chamber pressure differences and bullet diameter mismatch. Always verify ammunition compatibility before loading.