My first choice would be a Galil. Being so very cost prohibitive I would go with my second choice, an AR10 from Atak Defense. I have used the AR platform more than any other semi-auto and am comfortable and knowledgeable with it. The Atak Defense line are mad in my hometown, Barton Community a few miles south of Lucedale. I have been impressed with their products and I am a huge proponent of shopping local and supporting small business.
I don't know where you are located but if you find yourself within driving distance of Lucedale stop by Neith Firearms. They have a big selection of Atak rifles, pistols and suppressors. I have yet to try one of their suppressors so I can't knowledgeably comment on anything but the apparent quality of the build. Maybe someone that has one can comment one the sound dampening.