Here are the measurements I got off my track armor.mine is an m16 but it’s all the same. From the bulkhead to center of the hole 22 and 5/8, from the seat side of the track armor edge to the center of the hole it’s 9 and 1/2 . Hole diameter 1 and 3/4. Hope that helps
Man, I spent last weekend in St Louis, wish it would have snowed while I was there. Took my kids to the city museum, and lunch at fitz .