Rather than glue it, why not just put a small wood block in the back end of it? I use the follower on my wife's 6mm BR that I built on a 111 stagger feed. I'm not even sure you would need the block, there would just be a small gap in the back of the mag well that only you would notice. You still use your mag follower and spring, the single shot adapter is just put on top of that and held in place by spring tension. Give it a try and you will be fine, just make sure the gap is in the back of the mag well.

SHM

Sent from my XT1585 using Tapatalk