I am the owner of this clip and to my knowledge am the first ever to even know about "secret" (I put that in quotation marks because I don't know what to call it) reloads and have video prof of a secret reload in Insurgency Sandstorm.
I was messing around on the range in Insurgency when I picked up the M45 pistol and decided to shoot it a couple of times to see its recoil. What I did in order to trigger this reload, however, was: I press R once to reload and as the mag barely feel out and my hand reached up to it I quickly double pressed R and the secret reload happened. I don't know if doing that helped the opportunity for the reload to happen or if I just got lucky.
