Step 1: Clear the Weapon - Keeping the muzzle pointed in a safe direction, remove the magazine, pull charging handle to the rear and visually inspect the chamber to make sure that there is no ammunition present. Remove all live rounds from the working area and secure them in a safe place.
Step 2: Depress Magazine Catch Button - With an Ambi-Catch™ Tool, unsharpened pencil, back of pen or plastic drift fully depress the magazine release button on the right side of the weapon. You will continue to hold this button in the fully depressed position throughout the installation process.
Step 3: Unscrew Existing Magazine Catch - With the magazine release button fully depresed, the magazine catch will project from the left side of the weapon sufficiently to enable you to rotate it for removal. Rotate the magazine catch counter-clockwise until the treads are no longer in contact with the magazine release button.
Step 4: Remove the Magazine Catch - Remove the existing magazine catch from the receiver. You will be able to see the threaded portion of the depressed magazine release button through the hole in the receiver.
Step 5: Insert Shaft of Ambi-Catch™ - Holding the shaft of the Ambi-Catch™ perpendicular to the weapon, carefully start the threaded end of the shaft into the threaded portion of the depressed magazine release button. If you encounter resistance, unscrew the shaft and remove all components from the weapon (see "Note" below). Remove the magazine release button slowly and remember that the button is under spring tension.
Step 6: Screw-in the Ambi-Catch™ - Rotate the Ambi-Catch™ clockwise several full revolutions until some resistance is felt from the end of the shaft protruding through the open end of the magazine release button. The bottom of the lever will just clear the bolt stop bosses of the receiver when the shaft is fully engaged with the magazine release button.
Step 7: Align the Ambi-Catch™ - Once a sufficient number of full rotations have been made you must continue to rotate the Ambi-Catch™ until it is in alignment with the magazine catch slot of the receiver.
Step 8: Allow the Ambi-Catch™ to come to rest - Slowly release pressure on the magazine release button while guiding the body of the Ambi-Catch™ into the magazine catch slot of the receiver. Once the Ambi-Catch™ is fully seated observe the protrusion of the shaft of the magazine release button on the right side of the weapon. The end of the shaft should be flush with the top surface of the magazine catch button. Repeat Step 2 through Step 8 making one full rotation either clockwise or counter-clockwise until correct engagement is achieved. One half rotation can be made by removing the magazine catch button from the receiver and rotating it 180°.
Step 9: Function Test the Ambi-Catch™ - Test the Ambi-Catch™ with all of the magazines that you will use with your weapon. Test both primary and secondary methods of release. The Ambi-Catch™ should operate smoothly with a positive recovery. If recovery seems weak or the lever is extremely easy to depress; replace the spring (see Cleaning Instructions page).
Note: Some magazine release buttons may have excessive plating that will cause an interference between the threads of the shaft and button. To correct this a 10-32 NF-UNF tap may be used to clean up the thread of the magazine release button which is aluminum. Do not attempt to chase the threads of the shaft with a die as the surface is extremely hard. Your local gunsmith should be able to correct this condition for you.