Trigger Guard

• Mounting Options
  • Rivets
  • Screws
• Magazine Retaining Lever
  • Retaining Lever Spring
• Safety Stop
• Pistol Grip Mounting Plate

The Trigger Guard can be assembled during trunion assembly and should be fitted in relation to the front trunion.  Improper fitting of the trigger guard can result in improperly fitted magazines and resultant misfeed problems.

Mounting Options

Rivets 

1. One can rivet the trigger guard in place before the rails are installed.  This will limit the amount of space to fit the front trunion.
   
2. This can be done with a T-shaped bucking bar, that is used to press against the rivets from inside the receiver.  The slots produced by the "T" shape will allow clearance of the rails.
   
3. Some have been able to successfully use a thick piece of bar stock as a buck, such as a 1" square piece, with a notch cut in the side to allow clearance of the rails.  This would be used by securing the heads of the rivets in a "bucking die" to keep them from deforming, and hammering directly against the buck end of the rivets, in a fashion similar to that of Plinker's rivet jig.
   
4. A special trigger guard rivet jig has been designed that can be used with a press to rivet all five of the trigger guard rivets into place at once.  The following is the trigger guard jig diagram, originally posted by either Silver Dollar/7.62x39:

   

Screws

The trigger guard presents a unique challenge for a screw build project.  If you are performing a screw build then the four trigger guard screws will require smaller screws than any other point on the rifle.  The normal screw size of 10-32 can be used, but the heads are large enough that you will have to file them down to get all four screws to properly mount.  8-32 machine screws can also be used.

To do this, chuck the shank of the screw into a drill press, and spin at a low speed.  File the screw heads down to the appropriate size.  Hand-fit the screws to ensure the screws fit against each other.  When complete, it will look something like this:

    View after painting:  

The screws can be fastened to the receiver in one of two ways.  The first method is to tap the safety stop and the receiver, then screw everything down.  This method can be tricky because both tapped pieces have a tendency to "walk" when inserting the screws, so fastening down the trigger guard can be a tedious chore.  There should be enough thread "bite" in the receiver, however the second method eliminates this concern.  Here is a pic of the screws fastened using this method:

The second fastening method is to drill the receiver, safety stop, and trigger guard large enough to allow the screws to pass freely, then using either machine nuts OR a mounting plate inside the receiver.  This is probably easier and more secure.  

No matter how you fasten the screws, be sure that the screws are not so long that they impede operation of the hammer and the hammer spring.  If they touch the hammer spring, grind them down so that they are short enough to clear the hammer & spring.

Retaining Lever Spring

Assembly of the pieces should be done before attempting to insert the spring.  Clamp the pieces in place either in a vise, or with a C-Clamp, taking care to pad the pieces to keep from marring the finish.  The insertion of the retaining lever spring requires use of a punch or nail to "hold" the spring in place, while the retaining lever rivet pin is inserted from the other side.  

Pliers can be used to compress the spring before insertion.  In the same way a shim, drilled with two holes, may also be used to pre-compress the spring.  The retaining pin can be inserted while the spring is compressed, after which the spring can be relaxed into position.

Magazine Retaining Lever

The magazine retaining lever is mounted to the trigger guard frame by a rivet, which is flared on both sides with a counter-sink.  If a rivet shank is not available for use, many find that something such as a nail can be substituted for use as this "rivet".  

You must flare the ends of this rivet/pin to keep it in place.  

If you cannot find or use a rivet, a shaft could be threaded on both ends, and small-diameter machine screws could be screwed then loctited to keep this shaft in place.  This would not be a recommended solution.

One method to flare pins for the magazine release retaining lever:

1. Pre-drill the flat ends about 1/16" deep, 1/16" diameter.
2. Place a center punch upside down in the vise.
3. Hold the receiver over the punch, with the hole over the center punch.
4. Hold a second punch over the un-drilled side of the pin.
5. Hammer on the punch until the end with the divot is peened out.

Another (perhaps easier) method is to:

1. Take a C-Clamp and dremel a raised center "stamp" into the center of the face.
   OPTION: Weld a small round bead onto the C-Clamp and dremel the weld bead to shape.
2. Repeat on the screw side.
3. Drill the divots into both sides of the pin. 
4. Secure the receiver in the vise.
5. Center the C-clamp so that the stamps are located in the divots on the pin.
6. Clamp down the C-clamp to flare both the ends of the pin at once.

This second method requires a C-Clamp to be "dedicated" but you could make dimpling dies to sandwich between both sides the clamp and the pin but as cheap as C-Clamps are this may be counter-productive.  When you are done you can always dremel the raised bumps down flat again.

Safety Stop

The safety stop doubles as a washer to shim the magazine retaining lever at the proper distance from the receiver.  This can be used as a thickness adjustment if the magazine suffers misfeeds due to a misaligned front trunion.  This normally happens on Hesse/Vulcan receivers, but can be experienced any time the front trunion holes are not properly aligned.

To fix a misaligned magazine retaining lever, the safety stop can be filed down to bring the rear of the magazine closer to the receiver.  This can resolve many mis-feed problems when dealing with trunion hole alignment.  Other times, filing the top of the magazine retaining lever can be used to address some misfeed issues.

I have documented my safety stop resizing experience here.

AK-100 Pistol Grip Backing Plate

On AK-74M / AK-100 receivers, a special plate was added to reinforce the rear of the receiver.  This plate is completely optional, but for those desiring the most "realistic" AK-74M build, this can be added.  The plate is simply a shim in the shape of the pistol grip that is spot-welded to the bottom of the receiver.

This plate, along with more information about it, can be obtained from Tantal's website here:

http://tantal.kalashnikov.guns.ru/bstparts.html

Here are a few close-ups of current AK-100 series rifles, where the plate is noticeable:

AK-105:     AK-103:     AK-74M:

I made my own out of .065" (1.6mm) 4130 sheet steel. 

The template:

Using the template, I cut the pattern out with my cut-off tool.  A dremel cut off disk would work too.  It would probably require several disks, however, since the 1.6mm steel is relatively thick!

Here is the now-finished plate, with the tab bent upward.  This tab is optional and could be removed, cutting the top flat...

The fit:

I found that different pistol grips fit differently.  Since this is intended for the "modernized" rifles, I am most concerned about the AK-100 (black) grip.  I therefore tailored it for the larger pistol grip:

Spot-Welded, ready to be sanded down smooth and finished:

Sanded, ready for paint: