Note: All of this information goes for both the Beretta M9 and Beretta 92.
Working on service weapons for almost 10 years now and just recently is the first time I have ever seen this mechanically induced malfunction. This malfunction can be missed when going through a standard operator functions check on a M9 but will definitely be seen when you have a failure to fire.
What is the standard functions check on a M9?
Taken from the Army operators technical manual for a M9
Clear the gun of all ammunition before this inspection
- Depress the slide stop. Insert an empty magazine into the pistol, and ensure that the
magazine catch locks the magazine in place. - Retract the slide and release it. The magazine follower should push up on the slide stop,
locking the slide to the rear. - Depress the magazine release button allowing the magazine to fall free.
- Ensure the decocking/safety lever is in the safe (down) position. Depress the slide stop allowing
the slide to return fully forward. At the same time, the hammer should fall to the full forward
position. - Squeeze and release trigger. Firing pin block should move up and down,
Hammer should not move. - Place decocking/safety lever in fire (up) position.
- Squeeze trigger to check double action. Hammer should cock and fall.
- Squeeze trigger again and hold to rear. Manually retract and release slide while holding trigger
to the rear. Release trigger, click should be heard, hammer should not fall. - Squeeze trigger to check single action. Hammer should fall.
- If the above safety/function checks perform as indicated, pistol is mission ready. If the checks
do not perform as indicated, evacuate to organizational maintenance/next authorized repair
level
Here is what most don’t do within this function check..
- Squeeze and release trigger. Firing pin block should move up and down,
Hammer should not move.
As you are doing the functions check you need to watch for the firing pin block to move up and down. That block is part of one of the safety mechanisms within the gun. When the trigger on a M9 is pulled on both safe and fire positions it should cause that firing pin block to move up and out of the way of the firing pin.
To see this in action, strip the slide of the gun. Now take two punches. One you will use to push up on the firing pin block and another you will use to push on the back of the striker with the gun in the fire position. Look for the tip of the firing pin protruding. See it? Now you just inspected two things. Proper movement of the firing pin block and the firing pin tip not being damaged.
What causes the malfunction?
In this case, and the first case I’ve seen of the firing pin block malfunctioning, a broken firing pin block lever.
Mind you, I did not notice this break when first inspecting the frame so it is easily missed.
With a broken firing pin lever the ear that makes contact with the block as the trigger is pulled was entirely broke off leaving a flat lever with nothing to make contact.
It is also important to ensure that your firing pin is only protruding when that block is pushed up. There have been cases in which the firing pin was broken and was only found due to seeing it protrude without pressing up on the block.
Watching for proper movement and seating (top of the block being flush on the slide) of the firing pin block is crucial to the firing of the weapon. Everything else can pass on a function check until you fire live ammunition. If this issue is missed you will have a failure to fire due to the firing pin being blocked by the firing pin block.