Leaderboard

As said above that is the normal position of the head of the retaining pin. A hairs distance from flush with the side of the receiver. When you push the head to flush with the receiver's side, you are actually pushing the pin out of it's retaining spring groove, hence the tactile click you feel and hear. As proof of this, substantial pressure is needed to either push out the pin from the opposite side or pull it out from the head side to dislodge the spring from the retaining groove where it normally sits. When the head of the pin is a hairs width away from the side of the receiver, the pin's groove is being fully retained by the spring. This is what I have determined from my own M4.

Pressure pad for light really is the main thing..... Hard lesson learned from thumb nail ripping off. I know some have ground down metal on the the click caps to help prevent that from happening though.