The
M16 is the standard issue assault rifle for the US military.
Manufactured by Colt, the M16 series fire the 5.56x45mm NATO round, which is accurate but lacks
stopping power. It comes in safety, single, and 3-round burst trigger groups (except for the M16A3 which is automatic.) Auto fire was not used as it was deemed a waste of ammunition (and it usually is).
The original M16 was notoriously unreliable, due to low-quality ammunition, nagging issues with the ammunition feed, and the fact that the weapon was advertised as 'maintenence-free' (lol). The
M16A1 introduced the foward assist, which was used to clear the front section of the gun in the event of a jam.
After Vietnam, new ammunition was developed, which required a modification to the
rifling. This, along with other changes, created the
M16A2.
Later, the
M16A4 was adopted, featuring (among other things) full modding capability with Picatinny rails, which were already a feature on the
M4A1.
Contary to popular belief, as long as you keep them clean the newer models of the M16 don't jam all that often. Also, unlike what someone else claimed, a good
buttstroke with the '16 can ruin someone's day. It's quite
a sturdy weapon.
The carbine version of the M16 is the M4 (burst)/M4A1(auto).
The Marines train to shoot with the
M16 up to 500
meters.
"Now I'll just take him down with a well placed burst....Oh
cripes, a jam!"