From The TimeSplitters Wiki

M16
Ammo	?
Fire Rate bullets per sec/cartridge time	10 bullets per second
Reload Time	2 secs
Damage (per Single Shot) Head/Body/Leg	?
Type	Automatic
Zoom	Yes
Primary Fire	Fire
Secondary Fire	Fire
Games	TS

The M16 is an automatic weapon. It has a high rate of fire, similar to that of the tommy gun. The primary and secondary fire are the same meaning they do the same damage. The guns only appear in TimeSplitters and 2 M16s can be used at the same time.