$3,695.00Original price was: $3,695.00.$3,325.50Current price is: $3,325.50.
🚚 Ships to your local FFL — we handle the paperwork and coordinate with your dealer. Most firearms ship same or next business day. Local? Free in-store pickup in Roanoke, TX.
⚠ NFA ITEM — SHORT BARREL RIFLE (SBR) Federally regulated SBR under the National Firearms Act. BATFE Form 4, background check, $200 NFA tax stamp now $0 under OBBBA. Buyer must be 21+, US citizen, NFA-legal state. Allow 30–90 days. Western Sport handles all paperwork — call 817-393-4000.
The Maxim Defense SDX:508 is an integrally suppressed Short Barrel Rifle built to SOCOM-grade specifications. The SDX platform was developed from the U.S. Special Operations Command PDW solicitation — engineered for Tier 1 operators who demand maximum firepower in minimum length. At its core is the DSX-D suppressor with MonoKore™ Technology, a single-piece monocore baffle stack that Maxim Defense calls the most robust suppressor in its category. SOCOM table-tested across multiple calibers with no damage and no significant change in sound reduction. The SDX:508 runs 5.56 NATO, 7.62×39, and .300 BLK from its 8.5" barrel, with an overall length of 28.125" — hearing-safe, full-powered, and NFA-registered as a single unit.
Construction is military-grade throughout: 6Al-4V titanium and 17-4 stainless steel baffles, 7075-T6 and 6061 aluminum receivers, and a Diamond-Like Coating (DLC) finish with Type III hard coat anodizing. The HK-height rail delivers a more rigid upper receiver for optics. Arid (Flat Dark Earth) Cerakote finish. Manufactured in the USA. ISO 9001:2015 certified.
Maxim Defense Industries is a Minnesota-based American firearm manufacturer and ISO 9001:2015 certified company. The PDX and SDX platforms were developed directly from the SOCOM PDW solicitation — designed to meet the demands of Tier 1 operators who need maximum lethality in a minimum package. Maxim Defense builds its firearms from military-grade materials: 6Al-4V titanium, 17-4 stainless steel, 7075-T6 and 6061 aluminum. Every firearm is built to order in the USA.
Frequently Asked Questions
What is an SBR? A Short Barrel Rifle has a rifle barrel under 16″ and is federally regulated as an NFA item. It requires a BATFE Form 4 transfer, background check, and $200 tax stamp — now $0 under OBBBA.
What calibers does the Maxim Defense PDX/SDX fire? All PDX and SDX models are offered in 5.56 NATO, 7.62×39, and .300 BLK. .300 BLK pairs best with an integral suppressor for hearing-safe suppressed fire.
Does the SDX/PDX-SD come with the suppressor? Yes — the integrated DSX-D (SDX) or PDX-specific suppressor is included. The suppressor is part of the registered SBR and is not sold separately.
How long does NFA approval take? Typically 30–90 days. Western Sport handles all Form 4 paperwork in-house. Call 817-393-4000.
Is the $0 NFA tax stamp permanent? The OBBBA eliminated the $200 NFA tax. Western Sport recommends calling to confirm current status.
Why Buy From Western Sport?
Western Sport is a licensed FFL/SOT dealer in Roanoke, Texas (North Texas), FFL/SOT since 2007. We specialize in NFA transfers and handle all BATFE Form 4 paperwork in-house — so you get a smooth, guided NFA purchase experience. The $0 NFA tax stamp under OBBBA makes now the best time to buy. Call 817-393-4000 with questions.
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