I recently came upon a video of the Systema Training weapon system, which uses airsoft technology to simulate real weaponry. Unlike most airsoft guns, however, these weapons are modified to be as realistic as possible by doing things other airsoft guns cannot, such as lock the trigger upon running out of ammunition. Which brings me to my point. When loading in a fresh magazine, is there a button or catch on the side of the AR-15 series rifles that one can press to chamber in a round without pulling back the cocking handle? I ask this because this is a requirement on the Systema PTW.