As a police officer and soldier I was relatively embarrassed when I thought of posting this question/thread, but I told myself to get over it and ask for help from people who know.Bottom Line Up Front: I want a 9mm "pistol" utilizing the AR platform. Commonly referred to as an AR-9. My question is, should I buy one or should I undertake the task of building one?Although I have significant experience with many types of firearms, I have no experience "building" a firearm by ordering parts from different companies and assembling them. I have done a significant amount of research...