I apologize if this seems like a bit of a dumb question but, I've been wanting an AR 15 for a while and finally determined I have the means. And came to the conclusion that I liked the AR pistol in 300 blackout for its weight, portability, and impressive ballistics for such a short barrel. (not one of those delusionals who thinks it's suitable for long range shooting) but certainly good for home defense, range shooting, and some light hunting. Well, I have only been able to find conflicting information about the AR in MD. So simply, will it be legal for me to buy an ar lower on my 21st birthday and begin building an ar pistol? I also have some other questions about some components I would like to use and how they affect potential legality but, they seem moot until I have a better understanding of the general legality