Daniel Defense DDM4 300S SBR, .300 Blackout, No Magazine

Product Description

The Daniel Defense DDM4 300S, No Magazine is a semi-automatic NFA short-barrelled rifle chambered in .300 Blackout — 10.3" S2W heavy profile cold hammer forged barrel, 1:8 twist, pistol-length gas system, DDM4 Rail 9.0 quad rail, 5/8 x 24 TPI muzzle — built as the SKU Daniel Defense ships without a magazine.

The no-magazine part number exists for one reason: magazine capacity is regulated differently from state to state, and a rifle packed with a standard-capacity magazine cannot lawfully be shipped everywhere. The rifle is mechanically identical to the standard 300S part number.

And it is a rifle worth the paperwork. .300 Blackout puts a .30-calibre projectile through an AR-15 sized action using standard 5.56 bolts and magazines, and burns its powder in roughly ten inches — so this 10.3" barrel is the intended configuration. Subsonic loads behind a suppressor make it one of the quietest centrefire rifles you can own; supersonic loads make it a capable hunting gun. It weighs 5.77 lbs.

NFA short-barrelled rifle — what is involved

This is a short-barrelled rifle regulated under the National Firearms Act. It requires a BATFE tax stamp and an approved NFA transfer through a dealer holding a Special Occupational Tax stamp. Western Sport is an SOT dealer and handles these transfers routinely. We publish no legal advice or timelines here — send us a message and we will explain the process as it actually works. See our NFA firearms listing for related items.

Key Facts

• Brand / Model: Daniel Defense DDM4 300S
• Manufacturer Part Number: 02-122-17026-067 | UPC: 815604018272
• Configuration: No magazine — Daniel Defense ships this SKU without one
• Legal category: NFA short-barrelled rifle (SBR)
• Action: Semi-automatic | Caliber: 300 BLK (.300 Blackout)
• Barrel: 10.3", S2W heavy profile, 1:8 twist, cold hammer forged
• Barrel material / finish: Chrome Moly Vanadium steel; chrome lined, heavy phosphate finished, HP/MPI tested
• Gas system: Pistol length
• Muzzle device: Daniel Defense flash suppressor, 17-4 PH stainless steel, salt bath nitride
• Muzzle thread: 5/8 x 24 TPI
• Rail: Daniel Defense DDM4 Rail 9.0, 6061-T6 aluminium, Type III hard coat anodized
• Receivers: CNC machined 7075-T6 aluminium; Mil-Spec lower with enhanced flared magazine well and rear receiver QD point
• Bolt carrier group: M16 profile, Mil-Spec MP tested, chrome lined, staked gas key
• Furniture: Daniel Defense buttstock, pistol grip and vertical grip
• Magazine pattern: Uses standard 5.56 bolts and magazines
• Weight: 5.77 lbs | Overall length: 26 3/4" – 29 7/8" with muzzle device

Sourcing magazines for a Blackout rifle

Because this SKU arrives without one, buy magazines deliberately. The 300S uses standard 5.56 pattern magazines, but a magazine marked for .300 Blackout is worth having so Blackout ammunition never ends up in a 5.56 rifle by accident — that mistake is the one genuine hazard of owning both. Capacity limits vary by state and locality and change; confirm your own state’s current rules before ordering. Browse magazines and ammunition.

Ordering from Western Sport

Order online and we ship it to the licensed FFL dealer you choose near you — see how buying a gun online works. Western Sport has been a licensed FFL/SOT dealer since 2007, and everything we sell carries the full manufacturer warranty. Questions before you order? Send us a message.

Frequently Asked Questions

Q: Why does this 300S ship without a magazine?

A: Because magazine capacity limits differ from state to state and a rifle packed with a standard-capacity magazine cannot lawfully ship into every jurisdiction. Daniel Defense builds this no-magazine part number so the firearm itself can reach the customer, who then sources magazines that comply where they live.

Q: Is it still an NFA item without a magazine?

A: Yes. The magazine is irrelevant to that. It is a short-barrelled rifle under the National Firearms Act, so a BATFE tax stamp and an approved NFA transfer through a dealer holding a Special Occupational Tax stamp are required. Western Sport is an SOT; send us a message for our process.

Q: Which magazines should I buy for a .300 Blackout rifle?

A: Mechanically it uses standard 5.56 pattern magazines. In practice, buy magazines marked for .300 Blackout so Blackout rounds never get loaded into a 5.56 rifle by mistake — that is the one real hazard of owning both calibres. Confirm capacity rules for your own state first.

Q: Why is a 10.3-inch barrel right for .300 Blackout?

A: Because the cartridge burns its powder in about ten inches. Unlike 5.56, which needs length to reach useful velocity, .300 Blackout was designed around short barrels, so this is the intended configuration and it delivers a heavier .30-calibre bullet with more muzzle energy than a comparable 5.56 platform.

Q: How quiet is a suppressed subsonic 300S?

A: Subsonic .300 Blackout through a suppressor is about as quiet as centrefire rifle shooting gets, because there is no supersonic crack to manage. The pistol-length gas system is sized to cycle those loads. The suppressor is a separate NFA item with its own transfer; the muzzle is threaded 5/8 x 24 TPI.

Q: How light is this rifle?

A: 5.77 lbs, with an overall length of 26 3/4 to 29 7/8 inches including the muzzle device. That is lighter than most 5.56 carbines, which is the practical appeal: genuine .30-calibre performance in a package you can actually manoeuvre indoors.