I did some reading about the brave men of Operation Ivory Coast…the rescue of American POW’s from the Son Tay prison camp during the Vietnam War. If I understand correctly this was the first combat use of a ‘reflex’ type optic by U.S. forces. Some of the Son Tay Raiders used Single Point reflex sights on their GAU-5a’s.
I ended up having an opportunity to buy an authentic Single Point sight that was still in original condition complete with mount. The reading inspired me to install the Single Point sight and a ‘field expedient’ sling to my Colt CRXM177E2. The CRXM177E2 is part of Colt’s AR-15 Military Classics series.
One of the most popular MAC-V SOG photos of the war shows Maj. Joh Plaster with his XM177E2. The photo is shown below.
Here is a photo of John Plaster receiving a Colt CRXM177E2 from Colt employees. You can read about the event here: https://www.guns.com/news/2019/05/07/maj-john-plaster-gets-his-xm177e2-back-kinda
You can read more about John Plaster and the wartime use of the XM177E2 here: https://www.americanrifleman.org/articles/2019/1/24/behind-enemy-lines-with-the-car-15-rifle/