M16
The M16 was a series of automatic rifles made by Colt Firearms for the United States military. The M16 rifle and its variants saw extensive service with the US Armed Forces from the 1960s to at least the mid 21st century.

US Marine sentries used the M16A1 variant on board the aircraft carrier  and aimed them at Pavel Chekov during his arrest in 1986. ()

External links
 
 
 Weapons used in Star Trek IV: The Voyage Home
Hand-held weapons
Projectile weapons