Took this picture in Mexico last week. Didn't think anything of it at first, but then upon further examination, it appeared to be an AR10 or some variant like that. I didn't think these guys carried AR10's.
Took some more pictures of them as well. Saw a lot of M4's, FNC's, and G3's.
This is my little bro who asked the guy if he could take a picture with him.