Got a matrix aerospace ar10 that needs a bolt catch screw? here it is! - Guntec USA AR .308 Bolt Catch Screw

The Matrix Aerospace AR 10 is a Cadillac AR and the hurt on your wallet will confirm that if you buy one new. I got a deal at a pawn shop, but after the first trip to the range, it resulted in the bolt catch screw, spring and plunger coming loose and disappearing where only the great Kreskin or a Magic 8 Ball knows. Don't count on the original manufacturer lifting a finger to help you. I called, called again, sent emails and no one in their organization would lift a finger to help me find replacement parts. Wish I had an uncle on a Senate appropriations committee, but no luck there. The problem ultimately is there is no commonality of parts for the AR 10. DPMS and Armalite do not agree on much of anything. So I ordered screws from various vendors (Aero Precision was one) but even though they were good, quality parts, none of these parts worked. They would not thread up with the hole. So I ordered this little gem and SHAZZAM, it fit it like a glove. And Optics Planet sold it at a very reasonable price. Here's the final fly in the ointment. I finally found the Matrix Arms website and even though the price on their screw was three times as high as OP's, I ordered it anyway. Where's the fly there, you ask? Those folks still haven't sent me my Cadillac priced screw and that was well over a month ago. If it ever get's here, it better be gold-plated!