With a small piece of painters tape on the end of an extended 3/16 hex key, I install the grip screw by hand turning until tight. The painters tape holds the screw for easier installation. The same concept works for the flat head cap screws found in many build kits as well. Note: If your grip did not come with a lock washer or Loctite pre-applied, using a small drop of blue 242 Loctite will help hold the screw in place, although a lock washer is what the TM calls for. Tighten until snug.
Ensure the grip remained seated fully after tightening the grip screw. Some grips/receivers may have a very tight fit before the grip screw is installed. It may feel like the screw is “tight enough” yet the grip is still not seated fully. You can check for this by firmly grasping the grip after the screw is tightened, and checking for front and rear wobble. If any is present, re-seat the grip and re-tighten the grip screw. You should have little to no gap along the two noted red lines for most grips if installed properly.
Flipping the receiver back over on the vice block, I now stake the castle nut in two places (per the TM). Using an automatic center punch, I will swage part of the end plate into the notch on the castle nut. It may take 10+ cycles of the center punch to get the appropriate stake. Cycles may vary depending on how strong your auto-center punch is. This can also be done with a hammer and non-auto center punch. Much more care must be taken though to not damage any components though.
Process is repeated for the second stake location.
Install the stock by sliding it onto the receiver extension. It will stop until you pull up on the adjustment lever (if installing a plain M4 stock), or by lifting the lock bar on the below Magpul example.
Ensure the grip remained seated fully after tightening the grip screw. Some grips/receivers may have a very tight fit before the grip screw is installed. It may feel like the screw is “tight enough” yet the grip is still not seated fully. You can check for this by firmly grasping the grip after the screw is tightened, and checking for front and rear wobble. If any is present, re-seat the grip and re-tighten the grip screw. You should have little to no gap along the two noted red lines for most grips if installed properly.
Flipping the receiver back over on the vice block, I now stake the castle nut in two places (per the TM). Using an automatic center punch, I will swage part of the end plate into the notch on the castle nut. It may take 10+ cycles of the center punch to get the appropriate stake. Cycles may vary depending on how strong your auto-center punch is. This can also be done with a hammer and non-auto center punch. Much more care must be taken though to not damage any components though.
Process is repeated for the second stake location.
Install the stock by sliding it onto the receiver extension. It will stop until you pull up on the adjustment lever (if installing a plain M4 stock), or by lifting the lock bar on the below Magpul example.