DIY Lower Receiver Action Block (Vise Block) for the AR15

I'm going to show you how to make a lower receiver action block for the AR15 rifle.  These are very handy for building or cleaning your rifle.  You can buy these from Brownells or Midway for $10 to $50.  Or you can make your own for next to nothing if you have the right tools.  Even if you have to buy the T-bevel and the Dremel bit that are required, it costs roughly the same as the cheapest one you could buy and now you have a few more handy tools for future projects.  For example, both the bit and T bevel come in very handy to properly fit a new stock to a Garand.  If you don't have a Dremel tool, you need one anyway if you plan on doing much work on firearms.  If you don't have a table saw, find a friend who does and make him an action block too.  Also, this block can be modified to let you safely dry fire.  This comes in handy for trigger work.  Once you've made one, its easy to make more to have a spare, or loan or give to your friends.

Tools needed:

Table saw
T-bevel  ($4.97 at Home Depot or $2.99 at Harbor Freight)
Dremel tool
Dremel 194 high speed cutter bit (or similar cutting bit)
rule or tape measure
pencil
masking tape

Materials:

aprox 18" long piece of 2x4

Instructions:

First rip the 2x4 to a width of 2 3/8" (the longer interior dimension of the magazine well).  The shorter interior dimension of the mag well is 7/8".  You will want to mark the end of your board at 7/8" and set the height of your table saw blade to cut away all but 7/8" of the thickness of your board.  If you use a regular blade, you will have to make a lot of cuts.  If you use a dado blade, it will take fewer passes, but it takes time to change out the blade.  Using the miter gauge on your table saw (set at 90 deg), make multiple passes until you have about 2" inches of the end that is reduced to 7/8" thick.

Now fit that end into your lower receiver.  Use the T bevel to gauge the angle between the block and the bottom of the mag well.  Do this by placing the wood or plastic part of the T bevel along the edge of the board, and the metal part of the T bevel along the bottom of the mag well.  Lock the T bevel at that angle.

Now transfer that angle to the miter gauge on your table saw.  Loosen up the miter gauge and place the wood or plastic part of the T bevel against the miter gauge and the metal part of the T bevel against the saw blade.  Adjust the miter gauge and then tighten it back up.

Make several more cuts on your work piece until it fits into the mag well of your receiver nicely.  The finished product only needs to be 8-10" long, so you have room for mistakes/trial and error.  Now place a piece of masking tape on the side of your receiver just below the magazine catch on the left side.  Push the magazine release button in until you can rotate the magazine catch out and away.  Let it rest on the masking tape.  Now put the block into the mag well and mark the outline of the magazine catch.  Also make a mark along the top of the receiver so you can trim the block flush with the top.  Now use the cutting bit on the Dremel tool to carve a slot about 1/8" deep.

Trim the board along the top line in the table saw.  Now cut your block to length.  I cut mine to 8", but you make want it longer or shorter depending on your vise and preference.

You can screw a block of wood to the top to block the hammer for safe dry firing when working on the trigger.