Accurately shooting a rifle in the AR-15 family of rifles isn't that difficult. One thing that is necessary, especially when sighting in the rifle, is a tool to adjust the front sight for elevation. There are commercial tools available that are often dual purpose and can be used on both the A1 and A2 style sights. Sometimes it is more fun and satisfying to make your own tools instead of buying them. I don't have an A1 sight so this instructable is only going to show you how to make an A2 style sight tool The A2 sight is easy to identify, a front sight post with 4 adjustment divots is the A2 sight.
Front sight adjustment is tricky for some. To move the point of impact down, when the rounds are hitting to high, the front sight needs to be moved up. If the rounds are hitting to low the front sight needs to be moved down. If there is any interest I can do an instructable on the entire sighting in processs.
Step 1: Gather Your Supplies.
You will need just a few supplies and tools for this instructable.
A rotary tool with a cut-off wheel.
A pair of safety glasses
A sharpie marker
A spent cartridge case from either a .223 or .38/.357
The cartridge case can be brass or steel. I have used just the brass but I am guessing the steel case may be more durable.Nic
Step 2: Marking the Cartridge
There needs to be 4 evenly spaced prongs so we will take our cartridge and our sharpie and make 4 evenly spaced lines from the case mouth. These lines should be 2-3 cm long.
Step 3: Making the Cuts
Now that we have the four lines marked and have made sure they look evenly spaced we use our safety glasses and rotary tool to make cuts on both sides of each line. Try to make the cuts to the same depth. After you make the 8 vertical cuts, identify which areas are going to be removed and make a shallow score at the bottom of the cuts. This will make removing the waste areas much easier. Use a small pair of pliers to bend the excess metal and remove it from the cartridge.
At this point the adjustment tool is complete. You can use a small file to clean up the cuts and remove any sharp edges.
Step 4: Test Fit
After making the cuts and removing the waste pieces test fit the tool to your front sight. It may take a little adjustment to get the 4 prongs around the front sight. You may also want to trim the length of the prongs so they do not go below the bottom of the sight post base when pressed down, this will make turning the sight post easier.