After building a new 9mm AR, I was having some doubling and tripling happening. After taking a closer look at the trigger (JMT pack trigger) I was doing a function check and noticed that if you pushed forward on the hammer with the trigger depressed (after resetting the hammer) it would release (NOT COOL!!). There are some set screws that allow adjustment of it and I was able to get it to stop, but IMO a trigger should NEVER allow that. If you have one, be careful!