Replaced with new updated version:
PART NUMBER SCO-AC633
https://www.armorydynamics.com/SilencerCo-Alpha-Direct-Thread-12x28-AC633_p_1883.html
Replace your spring retainer, spring and piston for this fixed thread mount. It allows the use of the Octane 9 and Octane 45 on a fixed barrel firearm with thread sizes 1/2 X 28, 1/2 X 36, and 5/8 X 24. Made with stainless steel and given a black oxide finish.
Also compatible as a fixed mount for the Omega 9K and Omega 45K.
