itsmcgavinson
08-04-19, 14:45
The below site says 1/8" allen (hex) head, but others have stated 9/64". I'd buy them both but it appears the former is a needle in a haystack at least for drive bits.
http://www.maxicon.com/guns/optics/one_piece/ar15_onepiece_mounts.htm
http://www.maxicon.com/guns/optics/one_piece/ar15_onepiece_mounts.htm