M16/M4 Handbook. Erik Lawrence

      Zeros created with ballistic computer for M4/M855 with 2.5” sight height (height of EOTech on rail) have been rounded for ease of use. They will vary with different sight heights. Example: ACOG mounted on rail will have a slightly flatter trajectory vs mounted on the carrying handle, but wind deviations will remain the same for both.

      - 25m and 300m / 50m and 165m / 100m and 80m / 200m and 40m

      CHAPTER 4

      LOADING SEQUENCE

      Every time a Marine or Soldier loads his rifle, it should be done in the same manner. This action will ensure not only that the rifle is properly loaded, but also that all the accessories are in proper working order and properly adjusted.

      MAGAZINES

      The magazines were designed to hold 30 rounds reliably, and modern good-quality magazines will. The only drawback to loading 30 is that they may be a little harder to load into the weapon when the bolt is forward. Standard magazines will accept 31 rounds, but there is not enough travel in the spring to allow you to load it into the rifle, and if you do hammer it in, it will cause a failure-to-feed malfunction on the first shot because the pressure against the bottom side of the bolt carrier slows the cycling of the weapon too much. Never “upgrade” a magazine and carry it operationally without test firing it. Magpul followers are a good addition, but the standard green mil-spec follower has worked well for years. NOTE- Magpul base plates cause you to lose between 1 and 2 rounds of capacity. Magazine problems are usually caused by feed lips separating or a weak spring in a worn-out magazine. To check a magazine for serviceability, load about 12-18 rounds into a magazine, and strike it against your palm; if a round pops out, the magazine is unserviceable and will be prone to double feeds. Repeat this with a round on the opposite-side feed lip.

      NOTE

      When a magazine is bad, render it obviously unserviceable, and get a new one. Don’t DX/exchange it in a condition where it could be reissued and get someone killed!

      PREPARE FOR FIRING

      Before a Marine or Soldier goes to the range or leaves on a mission, he should always conduct his pre-combat checks (PCC) and pre-combat inspections (PCI). These should include: inspect/run a patch through the bore, ensure the rifle is properly lubricated, check the sling and all the accessories for serviceability and tightness, check that optics are clean/clear, and have batteries as necessary (always have spare batteries). Once that check is completed, you are ready to initiate movement. At the time you are given the command to load, the following steps should take place:

      1.Remove a magazine from a pouch or pocket. Ensure it is fully loaded and that the top round is on the right side. (Even-numbered rounds, i.e., 28 or 30, are on the right side of the feed lips. If you load 29, notice that your top round is always on the left).

      2.Place the magazine in the well until it clicks, and pull down to insure it is properly seated.

      3.Pull the charging handle straight to the rear and allow the hand to slip off as it reaches the rearmost range of travel.

      4.Remove the magazine and check that the top round is now on the opposite side. At night this check can be done by feel, so it is important to know whether you carry mags with odd or even numbers of rounds, i.e., 28 or 30.

      5.Place the magazine back in the well until it clicks, and pull down to insure it is properly seated.

      6.Hit the forward assist to insure the bolt and carrier are fully into battery.

      7.Close the dust cover.

      8.Check that the optic is tight, clean/clear, and turned on at the proper setting for ambient light.