A fast and easy California Compliant magazine lock solution for your AR-10 or AR-15. Better than the current pins on the market, this bolt on solution allows you to perform magazine changes faster than you ever thought possible. How it operates is a modified quick-release take down pin, which acts as a button to separate the upper from the lower just enough to disengage semi-automatic operation and automatically disable the magazine lock. Once your upper is separated and disengaged from semi-automatic operation, your magazine release is now operable. A simple tap closes the upper and re-engages the spring loaded take down pin and will quickly get you back in the fight. The Hellfighter Mod Kit is compatible with any AR-15 or AR-10.