Section 4: Demilling the parts kit

Parts kits usually come with some parts of the original receiver still in place. These need to be removed before the build can begin. In this section we will cover removing the receiver stubs,  the old rivets and the barrel. Whether your doing a screw or rivet build removing the barrel will make it much easier. 

You will need the following tools:                                             You will need the following materials:

3 lb hammer                                                                               Cutting oil

Set of punches                                                                            12mm socket

Vise grip pliers                                                                            6" piece of .500" key stock

Bench vise                                                                                   Roll of pennies

Drill press                                                                                    Band Aids

.120" drill bit

.250" end mill or Dremel with cutoff wheels

The first thing you will do is remove the barrel. This will make working with the rest of the parts much easier. Lock the front trunnion into the bench vise with the left side facing you. Holding a punch that is smaller in diameter than the barrel pin with the vise grips (If you do this the Band Aids may not be needed) Start to work on the barrel pin. It may take several good blows to get it to move. Once it is out place it in a safe location since you will need it later.

Now you can drive the barrel out. But first we need to make another custom tool. Drive the .500" key stock into the 12mm socket. This will be the ram for removing the barrel. Position the trunnion so that the front lips are on top of the vise jaws and the barrel is free to drop. Have a pillow or other soft cushion to catch the barrel when it comes out.

Use the pennies to protect the chamber. Place the ram and start beating. You will hear a loud "Pop" once the barrel starts to move.

The next step is to remove the old rivet heads. Start by removing the stock from the rear trunnion. If you are using the Dremel method, cut off the head of each rivet being careful not to cut into the trunnion or trigger guard parts. I have found that using the .250" end mill in my drill press works very quickly and is more controllable. You can order end mills from many places but I got 10 of them on ebay for $15.00 delivered. I start with the rear trunnion and use the end mill to remove the rivet heads. Once the heads are removed I pry the receiver stub off.

Next I drill through the rivet with a .120" bit. Go slow and use a lot of cutting oil. Pull out often to clean the hole. If the bit breaks off you can still get the rivet out but it will take way more pounding. Once the holes are drilled I set the trunnion on edge on the bench vise jaws and use a punch to start the rivet out. Once it is started lock the rivet in the vise and just twist the trunnion while pulling up.

Next remove the rivet heads from the front trunnion and pry the stub off. Use a small punch to knock out the rivets.

Next I lock the trigger guard assembly into the drill vise and remove the rivets from the inside. This allows more room to work and decreases the chance of damaging the parts. Remove the rivet backs and peel off the old receiver stub.

Cut the rivets flush with the mag catch plate and drill them out with the .120" bit. Next knock out the rivets and the demill is complete.

CYA message: This web page is posted for informational and educational use only. Any other use of the information on this website is solely at the user's risk