This is the gun that shot six young people and killed two of them in Washington State. It is a .40 calipher Beretta. 

Berettas (click here) just like this one are used in military combat. 


They are approved by and used by NATO and yes it is a semi-automatic.

The bullet below is a hollow point .40 caliper bullet. On the left side of the picture is the hollow point after it was fired and hits an object. If this is the type of munitions used by Jaylen this is what went through the heads of at least five of those young people, including himself.