Amicus
1
This appears to be a cantilever mount that allows a TA31 to be pushed back on the carry handle about 2.5". I’ve never seen its like before.
The link to see it is:
https://www.reddit.com/r/ar15/comments/rf9nwr/today_i_figured_out_the_carry_handle_mount_226/#lightbox
[ I am still learing how to use t his site. Also, I don’t have the rights to this photo and don’t want to publish the photo here.]
ETA: Got rid of useless stuff
Almost positive that’s just an extra hole drilled and tapped into the carry handle mount that’s part of every ACOG forging.
Amicus
3
Yep, you’re right. This is a TA31 mounted using the forward hole in the sight and the usual CH hole used for mounting. Don’t know what I was thinking.