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Will this fit on a blackout defense upper? 13.9 — 1 Answer

by Rob, from NC, United States Asked on June 20, 2022

Name Geissele 13.5in MK14 Super Modular Rail (4.5)
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Answered by Hunter, Gear Expert, from OH, United States, on July 05, 2022

The Geissele 13.5in MK14 Super Modular Rail will work with a Blackout Defense upper receiver. The Geissele 13.5in MK14 Super Modular Rail should also work with a 13.9" barrel.

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Last updated 2025-11-12 UTC.