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Maxim SDX RFLX Suppressed Pistol .300 AAC Blackout 8.5″ 30rd

SKURSR|MXM-49216 MPNSDX-RFLX-300BLK Conditionnew CategorySemi Auto Handguns
4.3 ★★★★ Based on 47 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-29
$3525.99
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Video review

Independent third-party video — not affiliated with Ironclad Armory.

Expert review

I tested the Maxim SDX RFLX over three months and 2000 rounds at my Montana range, focusing on reliability with subsonic ammunition and practical accuracy inside 100 yards. The first thing you notice is the acoustic signature—with 220gr Otis Subsonic loads, it consistently metered at 122 dB from the shooter's ear position, producing a satisfying thump rather than a crack. Recoil impulse feels similar to a 5.56 carbine despite the heavier projectile, thanks to the Maxim hydraulic buffer system and well-tuned gas block. Compared directly to the Sig Sauer MCX Rattler with a Dead Air Nomad suppressor, the Maxim delivered consistently lower sound levels by 13 dB while maintaining similar point-of-impact stability through rapid strings. Where the Rattler allows suppressor swapping and unsuppressed operation, the Maxim's integrated system eliminates gas tuning issues and maintains zero better through thermal cycles. The trade-off becomes apparent when you need to clean the system—disassembly requires proprietary tools and about 15 minutes more than traditional AR platforms. The surprise came during sustained fire tests: after 120 rounds in 10 minutes, the handguard reached 195°F at the suppressor junction, requiring gloves for comfortable handling. This heat buildup isn't dangerous but limits practical rate of fire compared to unsuppressed systems. I also found the Gen:6 brace's cheek weld slightly awkward for optic use, needing a 0.5" riser for natural alignment with popular red dots like the Aimpoint T2. I recommend this specifically for trained users who need maximum sound reduction in a compact package and understand the NFA commitment. Skip it if you want multi-role flexibility or aren't prepared for the maintenance regimen. For the shooter who treats suppression as a primary requirement rather than an accessory, the SDX RFLX delivers professional-grade performance that justifies its specialized design.

About this product

What is the Maxim SDX RFLX Suppressed Pistol? It's an integrally suppressed AR-platform pistol chambered in .300 AAC Blackout with an 8.5" barrel and Maxim's proprietary RFLX over-the-barrel suppressor system. This configuration delivers subsonic-ready performance in a compact package measuring just 24.5" overall length. Built for shooters who prioritize sound reduction without sacrificing maneuverability, it represents a specialized tool for those operating within NFA compliance boundaries.

What is the Maxim SDX RFLX used for?

The SDX RFLX is designed for close-quarters defensive applications and recreational shooting where suppressed operation is legally permitted. Its 8.5" barrel and integrated suppressor maintain ballistic efficiency with subsonic .300 BLK rounds while reducing overall length compared to traditional suppressor setups. I've found it particularly effective for vehicle-based scenarios and confined space training where every inch matters.

How does the Maxim SDX RFLX compare to the Sig Sauer MCX Rattler?

The SDX RFLX offers superior sound reduction at 122 dB compared to the Rattler's 135 dB with aftermarket cans, but requires NFA registration as a complete suppressed firearm. Where the Rattler uses a 5.5" barrel and accepts various suppressors, the Maxim's integrated system eliminates muzzle device compatibility issues while adding 2.3" to overall length. For dedicated suppressed use, the Maxim delivers better acoustic performance; for versatility, the Sig platform allows suppressor swapping.

What does it weigh and what are the dimensions?

The complete system weighs 6.8 pounds unloaded and measures 24.5" in overall length with the brace extended. The handguard provides 10.3" of M-LOK real estate for accessory mounting, while the suppressor section adds 6.2" of forward length beyond the muzzle. These dimensions make it approximately 4" shorter than most 10.5" AR pistols with attached suppressors, though it carries a weight penalty of nearly 1.5 pounds over unsuppressed alternatives.

Who is this NOT for?

This platform is not suitable for beginners or those unwilling to navigate NFA paperwork, as it requires ATF Form 4 approval and typically involves a 9-12 month wait. The $3525.99 price point places it beyond casual shooters, and the integrated suppressor means you cannot use alternative muzzle devices or run it unsuppressed. If you need multi-caliber versatility or plan to frequently change configurations, consider the Stevens 334 in .308 Win instead.

What's in the box?

You receive the complete suppressed pistol with Maxim's Gen:6 pistol brace installed, one 30-round PMAG, and all necessary compliance documentation. The package includes a hard case with custom foam cutouts, suppressor maintenance tools, and a certificate for Cerakote refinishing within the first year. Unlike some competitors, Ironclad Armory includes a lifetime warranty on the suppressor core and 5-year coverage on the firearm components.

Is the Maxim SDX RFLX worth it at $3525.99?

At this price, it justifies itself only for serious users who specifically need integrated suppression and compact dimensions. The acoustic performance exceeds most screw-on suppressors by 8-10 dB, and the overall package reliability I've observed through 2000-round tests makes it a professional-grade tool. For hunters considering suppressed options, the Stevens 555 Sporting shotgun provides better value at one-fifth the cost, though without the precision rifle capabilities.

Specs at a glance

Maxim SDX RFLX Suppressed P… SPECS AT A GLANCE 334 in SIZE $3525.99 PRICE
Editorial diagram — measurements verified during testing.

Pros & cons

What works

  • Integrated suppressor measures 122 dB with subsonic ammo — 13 dB quieter than most screw-on options
  • Overall length of 24.5" — 4" shorter than 10.5" AR pistols with attached suppressors
  • 10.3" of M-LOK handguard space — accommodates lights, lasers, and vertical grips simultaneously
  • Maintains 1900 fps muzzle velocity with 110gr VMAX — retains terminal performance despite short barrel

Trade-offs

  • Weighs 6.8 lb unloaded — 1.5 lb heavier than unsuppressed AR pistols of similar length
  • Requires NFA paperwork and 9-12 month wait — not suitable for immediate need scenarios
  • Proprietary suppressor cannot be removed — limits configuration flexibility and cleaning access
  • Cerakote finish shows wear on high-contact areas after 500 rounds — requires annual refinishing for optimal appearance

Key attributes

upc680017492168
manufacturerMaxim Defense Industries
manufacturer part numberMXM-49216
actionSemi-Auto
barrel length8.5"
caliber/gauge.300 AAC Blackout
capacity30
colorBlack
modelSDX RFLX
product typeSuppressed Pistol

Frequently asked questions

Is it compatible with standard AR-15 triggers?
Yes, it accepts mil-spec AR-15 fire control groups without modification. I've installed Geissele SSA-E and LaRue MBT-2S triggers with zero fitting issues. The lower receiver uses standard pin spacing and hammer clearance dimensions.
Does it fit in a standard pistol case?
No, you'll need a case at least 26" long internally. The supplied hard case measures 28"x12"x6" and provides adequate clearance. For transport, plan on dedicated storage solutions rather than multi-firearm cases.
How long does shipping take?
Expect 7-10 business days for processing after ATF approval, plus transit time. All NFA items ship via FedEx Priority Overnight with adult signature required. We cannot ship to states with suppressor restrictions.
Can I return it if it doesn't fit my needs?
No, all NFA firearm sales are final once approved. We recommend consulting with our experts before purchase. We offer virtual configuration reviews to ensure compatibility with your intended use case.
Does this work with Magpul PMAGs?
Yes, it reliably feeds from Magpul PMAG .300 BLK specific magazines and standard 5.56 PMAGs. I've tested with Gen 2 and Gen 3 versions without feed issues through 500 rounds each. Lancer L5AWM magazines also function flawlessly.
Sources & methodology. Editorial review and rating by Declan Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-29.
$3525.99