Question; I own two Glock 21SF's circa 2007. Both, ( not sequential serial No.'s ) are Ambi Mag release, with Picc rail. A friend told me that I should send them back to Glock, because of the problematic magazine release. He said that the part is not supported and that if it failed, I would end up warrantying the frame anyway. I called Glock and they were very nice. They said that although no Glock's ever had problems, they would be happy to exchange my ambi frames for left side, single side releases with regular Glock rail, at no cost to me. Is someone pulling my leg? I have never had a single issue with the pistol! Not one! A fellow at a local gun store said he'd never seen one, and that they were made for the Joint Service Pistol Trial ( last one ) and never officially released to the public. He went on to say that's why Glock was so "helpful". I like the pistol(s) and had a custom horsehide holster made. Another idea was to simply buy a 21SF frame from GB or Glockmeister and simply build a Frankenglock, for carry and place the original frame in storage. I don't think the situation is that dire. What say you Glock forum?