What are the 8 Functions of the M16A2 Rifle?

Answer 1

If you go to a drill sergeant and give the "cycle of function" of the M16 as "feeding, chambering, locking, firing, unlocking, extracting, ejecting and cocking, sergeant!" you will receive a GO at this station.

The problem is, it's out of order. Assume the M16 is pressed into your shoulder and aimed at an enemy soldier you need to shoot. There is a round in the chamber, the safety is off. When you shoot that guy, the following cycle of function will occur, in this exact order.

1) Firing. You will squeeze the trigger. The trigger will unlatch the hammer, which will be driven by powerful springs to strike the firing pin, which will ignite the primer in the round. The bullet will travel out of the barrel, go downrange and, hopefully, kill the enemy soldier before he can kill you. When the bullet passes the front sight post, some of the gases from the powder will go back down the gas tube - a thin steel tube running parallel to your barrel.

2) Unlocking. There are little metal lugs sticking out around the rim of the bolt. These are called locking lugs because they keep the bolt locked forward during Firing, so the bolt doesn't fly back, pull the cartridge out and let it blow up in your face. But to allow the weapon to cycle the bolt has to be unlocked, so the weapon rotates the bolt to align the lugs with the slots they pass through. It does this because the bolt will move back and forth within the bolt carrier, and there's a cam pin in a track that will turn it in an eccentric manner.

3) Extracting. An M-16 round has a rim at the base of it. The bolt grabs hold of this rim so it can pull the case out of the chamber. This happens now.

4) Cocking. By the time the bolt carrier's about halfway back, it will have pushed the hammer down and latched it in place.

5) Ejecting. When the bolt gets far enough back that the empty case can clear the chamber, a spring-loaded pin flips it out of the weapon. At the same time, the follower in the magazine will have pushed the next round up so the bolt can grab it. If the magazine is empty, the follower will push up the bolt catch. This way you'll know to switch magazines for a full one.

6a and 6b) Feeding and chambering. These go together. When the bolt gets all the way back, a spring-loaded buffer will force it back forward. The bolt will strip the top round off the magazine (feeding) and shove it into the chamber (chambering).

7) Locking. The locking lugs on the bolt will hit home before the bolt carrier does. In the carrier's last little bit of travel, the same cam pin that rotated the bolt into the unlocked position in step 2 will rotate it back to the locked position.