I am in the process of converting a Ruger Mark 2 pistol into a carbine. I have a 16.5" barrel coming from Clark custom gunsmithing and I am going to make the buttstock myself. I have a couple of ideas for the buttstock one being to attach it to the receiver, the other being to attach it to the grip frame. What do you guys think would be the more comfortable/ergononmic attachment point? Also I am kinda paranoid about attaching the buttstock to the grip frame and possibly getting into the potential SBR realm since it could then be attached to a regular pistol upper creating a SBR. I have zero interest in going through the process and getting the stamp for an SBR. I only intend on this being a carbine rifle configuration weapon. I think it would look better and feel better if the stock were attached at the grip frame, but am concerned about potential red flags by attaching it there. I also like the ability to have a sort of "break down" gun by removing the grip frame (stock attached) and the upper barreled assembly for compact storage and portability. Thoughts????