Gunsmith mill work needed, but a great upgrade - Dark Storm Industries Ambidextrous AR-15 Bolt Catch

You will have to mill .480” below the top of the lower and remove material off of the side of the lower just above the mag release. I did it by hand using a 4mm or .1575” Dremel bit and electric Dremel and then Birchwood aluminum black after smoothing my cuts with fine Dremel sanding bits to make it black again. Once done it works great! This Ambi bolt catch does not come with the spring, plunger, or pin. The Ambi bolt catch does not come with instructions. You will need to call dark storm for pdf of where to cut. If you do not have hand milling or machine milling experience or skill then you will need to pay a gun smith to modify your lower.