If you are using the Tactical Machining jig, you must mount the jig in a good vice that holds it straight up and down. Make sure you set the depth so that you do not drill to deep in each of the two pockets that you will be milling out. Drill out each corner of the fire control and rear lug mount area to within 1/16" of the proper depth, use a 1/4" drill or slightly smaller. Each hole should be drilled with the fixture firmly in a vice. It will take some time to keep moving the vice but it is worth it to have a good part when you are done. Once all of the corners are drilled to within 1/16" of the correct depth, drill rows of holes between these holes as close as you can to the previous hole without breaking into it. If you break into the hole next to one already drilled, it will go into that hole and not straight down. If you do this accidentally, skip it and continue until you have as much as you can drilled out of the pocket.
When you are done drilling, vacuum up all of the chips (You should do this as you go anyway.) Replace the drill bit with a two flute 3/8" end mill. A 2 flute end mill can "Plunge" or be able to drill straight down, many 4 flute end mills cant plunge.
Re set your depth so you go to the correct finished depth. Use the end mill to "Drill out" the metal between the holes you drilled. Do not cut into the jig or touch it with the end mill or your finished product will be out of spec (But would still work unless you cut through the side or something).
When you finish cutting out off of the metal in the pocket, see if the trigger hammer and upper will fit in the finished pocket. If it is to tight, use a dremmel tool and the 1/2" sanding drums to open up the pocket and smooth out any thing that remains.
It is like making a wooden duck, you take wood and remove anything that does not look like a duck. In this case you use the jig to guide what needs to be milled out, the dremmel will remove the small metal left between the drilled holes. If you dont have a dremmel, use the drill press and the dremmel sanding drum on it at high speed but be aware that he drill head may fall off if you press hard sideways on it. Never side mill with a drill press, the head will fall off since it is only held on by a taper. If it falls off it will roll and can cut you and your receiver up.
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