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Desert Design & Development DEFCON 4SDK 9mm Suppressed Barrel System


NFA Rules Apply

In state buyers come to MR SILENCER to consumate the purchase.

I have the digital fingerprint kiosk here in shop.  All Trustees must use the kiosk, and the passport photo feature.

Everything 41F done in house, no Sheriff needed.

Out of state buyers must have a copy of their local FFL/SOT sent to with Order # attached within 7 days.

Transfers initiated within 24 hours or receipt of FFL/SOT.


The DEFCON 4SDK 9MM System is our integral suppressed 9MM system for the AR-9MM platform. Its blueprinted port design and large volume suppressor makes it ideal for your stealthy needs. Based off the MP5-SD design, we’ve improved the suppression, increased the accuracy, and made it work for the vastly popular and familiar AR-9MM platform.

If you have an existing AR style 9MM upper/lower (regardless of manufacturer), this system should work for you. Please take note of the suppressor diameter. If your existing forend is too narrow, you will need to replace it before installing. This requires a standard diameter forend that has an I.D. of 1.75″ or greater.

You really need to see/hear this to fully appreciate and understand just how quiet this system is.

Not looking for a 9MM platform? In 2017 we enter production of our 40 S&W, 45ACP, and 10MM models. Most calibers are also available in our shorter “K” series. It’s features a 1″ shorter barrel and 4″ shorter suppressor, for a more concealable carbine.


Barrel: 5.75″ ported, match grade, 1:10 twist, made from 4140, parkerized

Suppressor Length: 8″, 9.5″ with barrel installed
Diameter: 1.625″

Weight: 13.7oz, 21oz barrel installed

Material (suppressor): 6061-T6 Aluminum

Serviceable: SEALED / not recommended
Sound Reduction: +/- 40dB

This is the “K” Model, specifically designed for the shortest most compact integral 9mm upper around.  The ported barrel keeps nearly all ammo in the Subsonic realm.  An amazing add to your SBR lower, either via Magwell adapter in a standard magwell, or a Colt or Glock magazine fed lower.


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Additional information
NFA Buyer Location

Arizona Buyer (Requires In-Shop Paperwork), Out of State Buyer (Includes Flat-Rate Shipping)