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Dead Air Armament Sig MOS Adapter Suppressor

$45.00

🔇 No Form 4 needed — since October 9, 2026 a suppressor transfers on a standard Form 4473 and background check, with no tax stamp or wait. Texas buyers can complete it with us; out-of-state orders ship to an SOT dealer in your state. How it works.
Product Code: DAV-DA420 Category: Brand:

Dead Air Armament Sig MOS Adapter is a black steel suppressor adapter with a 1/2×28 thread pitch. It is for Sig MOS owners who need a 1/2×28 threaded interface for their muzzle gear.

  • Thread pitch: 1/2×28
  • Made for the Sig MOS platform
  • Steel construction
  • Black finish
  • Dead Air Armament part number DA420

SKU: DAV-DA420 · Mfr part #: DA420 · UPC: 810128161244

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Product Description

Update, October 9, 2026: ATF no longer requires a Form 4, tax stamp, fingerprints or registration for suppressors, short-barreled rifles, short-barreled shotguns or AOWs. They now transfer on a standard Form 4473 with a background check. Anything below that mentions a Form 4, a wait or a tax stamp was written before this change. What changed

The Dead Air Armament Sig MOS Adapter is a steel adapter with a 1/2×28 thread pitch, made for the Sig MOS platform. It comes in a black finish, and the manufacturer part number is DA420.

This is a single-purpose part. It is built to work with Sig MOS, and it gives you 1/2×28 threads. That is a common thread pitch for muzzle devices, so it gives you a clear starting point when you pick out the rest of your setup.

Who it suits

This adapter suits Sig MOS owners who want to run threaded gear on their pistol. If you already have a suppressor, flash hider, compensator or thread protector that uses 1/2×28, this is the piece that connects the two sides. Steel is a sensible material for a part that sits at the muzzle end of the gun.

Pair it with any 1/2×28 muzzle device you plan to run. Check that your suppressor or other device uses the same thread pitch before you order. If you are not sure whether your Sig MOS pistol and your muzzle gear will work together, ask us and we will help you sort it out.

Dead Air Armament Sig MOS Adapter Suppressor Specifications

Thread Pitch 1/2×28
Material Steel
Finish / Color Black
UPC 810128161244
Mfr Part # DA420
Shipping Weight 0.8 oz (boxed)

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. See our NFA guide for the current federal rules; state law still applies.

Frequently Asked Questions

Q: What thread pitch does the Dead Air Sig MOS Adapter use?

A: 1/2×28. Any muzzle device you plan to run with it should use the same thread pitch.

Q: What is the Dead Air Sig MOS Adapter made of?

A: Steel. It has a black finish.

Q: Is the Dead Air Armament Sig MOS Adapter made for Sig MOS pistols?

A: Yes. It is made for the Sig MOS platform.

Q: What is the Dead Air Sig MOS Adapter part number?

A: DA420. The UPC is 810128161244.

Warranty and Manufacturer

Covered by the Dead Air Armament factory warranty; warranty terms come from Dead Air Armament.

Additional information

Weight 0.050 lbs
Brand Dead Air Armament
Finish

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Buying a suppressor now: a Form 4473 and a background check. No Form 4.

Since October 9, 2026, ATF no longer requires a Form 4, tax stamp, fingerprints, photos or registration to buy a suppressor. It transfers like any other firearm: you fill out a Form 4473, pass a NICS background check, and it is yours. No months-long wait.

  • Texas buyers: suppressors are legal under Texas law. Western Sport has been an SOT / Class III dealer since 2007.
  • Outside Texas: we ship to an SOT dealer in your state, who completes the 4473 with you. Your state’s law still decides — some states ban suppressors, and some only allow ones registered with ATF.
  • Want it registered anyway? ATF still accepts a voluntary Form 4. Ask us.

What ATF changed on October 9, 2026
How buying a suppressor works now
Questions? Send us a message.

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