Radical Defense MK1 Mod 1.5, PDW, SBR, 5.56 NATO, 6.5″ Barrel, Black, 30 Rounds

The Radical Firearms PDW SBR takes the 5.56 AR-15 platform to its most compact configuration — a 6.5-inch barrel that puts this firmly in Personal Defense Weapon territory. The 6.5-inch barrel is shorter than even a standard MK18 (10.3″) or a typical SBR lower (7.5–10.5″), placing it in the PDW class where portability is the entire point. At this barrel length, 5.56 NATO velocity is significantly reduced — muzzle velocity will be in the 1,800–2,100 fps range with M855, versus the 3,000+ fps of a 20-inch service rifle. The tradeoff is a platform that folds, carries, and deploys in extremely confined spaces.

Radical Firearms, based in Houston, Texas, builds AR-platform firearms at a price point that makes NFA ownership more accessible. The PDW SBR at $1,999 is positioned as a working-class SBR — the paperwork cost is the same whether the lower receiver is a $400 Radical or a $2,500 Daniel Defense, but the total investment is substantially different. For buyers who want a short-barrel SBR configuration for practical use without the premium-tier price, Radical Firearms is the answer.

Radical PDW SBR 5.56 Specifications

Why Buy From Western Sport?

Western Sport is a licensed FFL/SOT dealer in Roanoke, Texas, specializing in NFA suppressors and SBRs since 2007. We are an authorized Radical Firearms dealer and handle all Form 4 NFA transfers. Our team knows every product in our NFA inventory. Call 817-393-4000.

FAQ — Radical PDW SBR 5.56

Is 5.56 from a 6.5″ barrel effective?

At 6.5 inches, 5.56 NATO velocity drops significantly versus longer barrels. However, the PDW SBR is optimized for close-range (0–100 yards) scenarios where a compact platform is more important than maximum velocity. Modern 5.56 defensive loads maintain terminal effectiveness at reduced velocities. This platform is most suitable for confined-space use, vehicle work, or any scenario where a full-length or standard-SBR-length AR is impractical.

Is this suppressor-compatible?

Yes — with a muzzle device adaptor or the appropriate suppressor for the barrel’s thread pitch. The 6.5″ barrel will be significantly over-gassed when suppressed versus a longer barrel; an adjustable gas block is recommended for extended suppressed use.

Recent eForm 4 approvals have been coming back in about two weeks or less — see our NFA wait times guide for current figures.