You can save yourself some time and buy premade sideplates, but here is how I made two sets of them for about $10. They are slightly oversized for a final fitting in the area of the rear filler and the bottem edge. You need about .040" overlap above the stock tang, trigger group, and rear filler since the receiver is round. You could in theory measure the stock tang and trigger group heigth and just make it .040" taller, but it would leave you no room for error. I first made a rough template from some thin cardboard (a pepsi box) that had a square corner and long straight top. I mounted a trigger group in a demilled stock tang and mocked up a rear filler onto the front lug of the trigger guard and rough measured it a little under 8" from the rear of the sideplate to the inside front of the rear filler. I then removed a stock tang from demill receiver by knocking out the rivets with a drift that was about 1/2 the diameter of the rivet. Hit them hard or you'll just expand the rivet more and you'll have to drill it out. Then I traced the demilled tang section on the cardboard. Once I had my rough template I cut two, 2"x9" strips from a 9"x9" section of .080" 4130 sheet steel from wicks aircraft. I squared up the two pieces and tack welded them together at the lower left end that would end up as scrap and the right edge. I traced out my template on the steel and cut the bottem profile. When I was happy with it I cut the end of the stock tang area out of the sideplates, leaving the rear filler weld to hold the two sideplates together at this point. Next I clamped the stock tang in its spot and aligned it so it was square by measuring the distance from the bottem of the little shelf right in front of the charging handle guide to the top of the sideplate (with the .040" overlap on top) and making a mark about 5" forward of this same measurement (about a half inch). Then I took a straight edge and placed it in the cocking handle shelf of the stock tang and adjusted the stock tang until the straight edge was on the mark I had made. I put another clamp on the tang and sideplates and drilled the sideplates through the 3 rear stock tang holes with a 5/32" drill bit. Then I cut the rear filler area of the sideplates off at 8" which will leave me about 1/8"+ for final fitting. I will not cut the rear filler rivet holes or trim the sideplate length until after I repair the rear filler.