I'm the proud owner of a new no box, unfired MR556A1 that came with four HK mags and a HK Factory soft case. I paid $1,894.25 shipped, how did I do? Secondly, I understand the bolt carrier is filed down so as to not function in full-auto. I want to put it on top of my class 3 model 601 so what needs to be changed-out to make it work. Provided it can be done and the parts are available at less than an astronomical price. Finally, has anyone had experience with using an Aimpoint Comp 5 with a Scalarworks mount on a MR556A1 and what was your evaluation?