AK Trunnion Rivet Hole Drilling Fixture
although strictly speaking you don't need it. just press the barrel into trunnion, chuck barrel into vice, line up drill/spindle with the trunnion hole, fix the vise to the drill table so it doesn't move. slide receiver shell over trunnion until it bottoms out against lower rails and then drill a hole in a receiver. rinse and repeat for all holes. small tip: drill a small hole first with a small drill bit then pen it up with a larger ones to final diameter. use cutting oil and low speed- receivers are hard.
as far as rear trunnion you can use a piece of 2x4 to screw trunnion sideways and chuck that into vice and repeat the exercise same way as for the front trunnion.