Has anyone tried one of these with their CMMG or other .22lr upper? Allows you to use the S&W 15-22 magazines and gives you the bolt hold open function. Since my son has the 15-22 and I have the CMMG, this is interesting. Will allow me to consolidate to one type of .22lr magazine and provide a function that my CMMG rifle does not have....if it works. http://www.redi-mag.com/index.php?l=product_detail&p=52 Any thoughts on this?