Trying to find out what kind of 308 style lower i got in a parts lot with bunch loose ar parts including a 308 style 80% lower. But after milling it out and spraying it with alumihyde i realized a regular bolt catch pin system wasnt gonna work. There and extra cut out tab on magwell side of the bolt catch slot with a threaded hole through to the magwell. I havent ever seen any other lowers with this design and means of attaching bolt catch. Hopefully the following pics will help someone on here to help me. I dont have any idea of maker and can find nothing anywhere online about this design. Thanks.