I'm not sure I am missing a screw or something, either which way my mags with this coupler are pretty loose. I saw someone used heat shrink tubing to go over the coupler. Can someone tell me the size and diameter of a shrink tube I would need. I went to HD and they had many kinds. Thanks,
here is a pic of the mags, I pushed it down to show what it looks like when it's loose, and it slides like that pretty easily:
here is a pic of the mags, I pushed it down to show what it looks like when it's loose, and it slides like that pretty easily:


















































