Welcome to The Armory, where you can find original Adaptive Defense Concepts designs and other useful items we highly recommend.
Unfortunately, we do not accept orders from states where the addition of our products (such as flash hiders) to firearms may conflict with local laws such as California, Connecticut, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New York, and Rhode Island. It is the responsibility of the purchaser and end user to ensure the use of these products is lawful in their place of residence.
December 2025 NOTE: We are not (and never have been) affiliated with Lucas Botkin’s “Adaptiv Defense.” Adaptive Defense Concepts LLC has been in existence since 2011. Adaptive Defense Armory LLC started in 2020.
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Complete Upper - 18" Rifle Length
- Description
These upper receiver groups begin with a T-marked government-contract M-4 upper receiver laser engraved with our logo. Barrel flanges are lapped and "trued" for top-notch accuracy. Builds feature mid-length Adaptive Defense Armory rifle-length handguards and gas blocks with black nitrided gas tubes. Uppers are headspace checked and test-fired.
Barrels are Mk12 SPR/DMR contour 18" nitrided stainless barrels with a 1-8 twist.
Options include:
- Bolt: No bolt, Phosphated mil-spec bolt, Nitrided "enhanced" bolt
- Charging Handle: No charging handle, USGI, or Adaptive Defense Co-branded "Rack" charging handle by Battle Arms Development.
- Flash Hider: None, USGI A2, or Adaptive Defense "Rook."