Yeah, I've seen the reviews of that rail adapter. The loose pin thing is all about the hole size of the existing stud's hole - they chose to supply one pin and that means it will be a one-size-fits-all kinda thing, so it will err on the small diameter size. As far as the pin falling out, looks like it can't as the rubber spacer holds it in and attaching the actual pic rail with the 2 machine screws is s'posed to lock it all up - I've seen this in YouTube vids. There's also s'posed to be a 5* angle of adjustment, so that the rail itself can be made parallel to the bbl. This all sounds good, but the proof is in the actual installation and the final functional results. I have this Caldwell pic rail adapter coming, along with a Wiser off bbl MS V3 mount. I shall report back here the good, the bad, or the downright ugly.