1.125-28 Alpha Direct Thread Mounts




This adapter allows you to use your 1.125-28 threaded Alpha (also Harvester .300) pattern suppressor in direct thread configuration.  Stainless mounts install/remove with a 12-point wrench/socket, pin wrench or hook type spanner wrench.  The standard (short) version of the stainless mount has a 1/2″ deep threaded bore for most fixed barrel pistols and carbines, the long version has a .625″ threaded bore for AR length barrel tenons.  All stainless versions are barrel shoulder register, including metric; these will NOT register on the muzzle.

The M13.5×1 LH Stainless mount has the 25° Sig taper

Stainless Alpha Direct Thread Mount specs:

Material: 17-4 H900 stainless steel
Length: .64″ (.74″ for M13.5×1 LH Sig Taper mount)
Male thread length: .4″
Flange thickness: .15″
Flange diameter: 1.2″
Weight: 1.1-1.3 ounces
Internal thread: Choose option, all are through-threaded unless otherwise noted.
External thread: 1.125-28

Installation and removal can be accomplished with several tools, including a pin wrench or spanner wrench, but 17-4 mounts are designed with a 1-1/16″ 12 point wrench or socket in mind.

In stock Natural finish or Black adapters ship 1-2 business days. Other color options add up to 10 business days.

Want to know more about Alpha pattern threads? Learn more about it here (Scroll to bottom): https://www.eccomachine.net/our-faqs/

Additional information

Alpha DT Muzzle Thread

.578-28, 1/2-28, 1/2-36, 5/8-24, 5/8-32, M13 x .75, M13.5x1LH Sig Taper, M14x1LH, M15x1, M16x1LH, 11/16-24, Ultralight .578-28 Aluminum, Ultralight 1/2-28 Aluminum, Ultralight 9/16-24 Aluminum, Ultralight M13.5×1 LH Aluminum, Ultralight M16x1 LH Aluminum


    Bill Eisel
    June 8, 2023
    I received my alpha direct thread mount, and it is engineered and manufactured perfectly. I’d rate it better than SilencerCo’s and I received it quickly. Kudos to ECCO!
    Rich S.
    December 14, 2022
    So glad I found EccoMachine.net! I couldn’t believe it when SilencerCo did not make the two Alpha direct thread mounts I needed for my Omega 45K. The ones I received from EccoMachine fit like a glove and cost much less than SilencerCo’s. I highly recommend! #BOYCOTTGoDaddy #BOYCOTTPayPal
    December 13, 2022
    This product is of the highest quality and looks great also. Owner made sure I got what I needed for my purposes. Outstanding customer service and support.

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1.125-28 Alpha Direct Thread Mounts
1.125-28 Alpha Direct Thread Mounts
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