The “Sweet Spot”
The AK Master Mount™ side rail is held to the AK receiver wall by side compression. The underside of the two Allen head screws must compress firmly against the right outside receiver wall in order to have the adequate compression needed to keep the side rail tight against the left receiver wall.
So if you are experiencing slight movement of the side rail after installation, remove the Allen head screw from each hex pin to ensure the end of that pin is not flush with the outside receiver wall. Because the receiver walls actually flex inward during tightening of the Allen head screws, you want the shaft end of the hex head pins inset into the right receiver wall. Remember we are working with an AK, so there can be variations in receiver width.
The quickest way to check if pin length is the issue for your side rail’s movement is to add a couple of washers underneath the Allen head screw before installation. Just make sure the center hole in the washer is bigger than the hex pin shaft’s diameter.
This in effect simulates a wider receiver and ensures the underside of the Allen head screw is actually compressing against the outside receiver wall and not just “bottoming out” on the shaft end of the hex pin. Once this diagnosis is confirmed, remove the washers and use a metal file to remove some metal material from the shaft end of the hex pin. Do not worry about removing too much.
Century Arms™ VSKA rifle:
Our side rail kit will work after some modifications to the back side of our side rail because of the rivets Century Arms installed where a traditional side rail would have been installed on the receiver. For example a small part of the first rivet head (in front of the hammer axis pin) hits the leading back edge of our side rail. You will need to remove a small amount of metal from the back of our side rail (like with a dremmel) so it will lay flat against the side of your receiver.
Also part of the second rivet head hits a small part of the mid section of our side rail so a little amount of material would also have to be removed here for adequate clearance. I have attached a picture showing these areas of contact.
Then pair our side rail kit with our AKM version (rear biased or full length) optic mount.
Troubleshooting Fitting Issues – Possibility 1
Unfortunately many AK builders get a little sloppy in their manufacturing tolerances. If optic mount handle closing resistance is felt, or there is still slight optic mount left to right wiggle despite a hard to close handle, there may be interference on the rounded back portion of our handle. Background: Our optic mount is the only one on the market where the back of the handle physically rotates into the side rail’s central cut-out in order to “lock” our optic mount into the side rail. Possible points of interference: (1) the side rail’s central rivet head not flush with the floor of the side rail’s central cut-out. (2) the side rail’s central cut-out slightly off center (see possibility #2 description below). Both of these scenarios will interfere with the back of our handle properly rotating into the side rail’s central cut-out. Clues: look for finish wear on the lower, rounded back protrusion of our handle. See attached picture for an example of this. Treatment: use a dremmel / metal file to remove a small amount of material on the back of our handle exactly where the finish wear is seen OR from the top of the central rivet head if this is too tall. This will provide the needed clearance for the back of our handle to full close properly.
If the side rail’s central cut-out is slightly off center, the rounded back of our handle can hit the vertical edge of the side rail’s central cut-out and cause handle closing difficulty and / or push our optic mount up and away from the side rail. Clues: look for finish wear on the lower rounded back protrusion of our handle, or finish wear on the side rail’s front surface. See the attached picture for an example of this. Treatment: use a dremmel / metal file to remove a small amount of material on the back of our handle exactly where the finish wear is seen. This will provide the needed clearance for the back of our handle to fully close properly.
The side rail’s rear rivet head protrudes above the base plate of the side rail and hits the back end of our optic mount when sliding onto the side rail. This scenario results in resistance being felt when the optic mount is slid 1/3 of the way onto the side rail. The end user misinterprets the resistance to the clamp bar being raised too high. Clues: look for finish wear on the top of the rear rivet head OR a small “ding” at the end of the dovetail cut-out channel on the back of our optic mount. See attached picture for an example of this. Treatment: use a dremmel / metal file to remove a small amount of material from the rear rivet head OR to make a shallow scalloped shaped recess at the end of our optic mount’s dovetail cut-out channel. Just make sure to leave enough metal present to make contact with the end of the side rail when the optic mount is installed.
Using the Enhanced Safety Lever on a Milled Receiver:
Because our AKM version enhanced safety lever is made for a stamped metal receiver, its “gap” is sized accordingly for the thinner wall thickness of the stamped receiver. Our AKM version Enhanced Safety Lever can be modified to fit the thicker metal receiver wall of a milled receiver by using a dremmel or metal file to enlarge this “gap.” Remove metal from the vertical face of the milled paddle part as show with the red arrows in the accompanying picture. Do frequent test fits so as not to enlarge this gap too much. Touch up with black paint when done.