After
WWII, a
study done by the
US Armed Forces showed that many of the troops that got sent to war did not have
adequate psychological preparedness to kill other human beings.
Some actually hesitated to fire their M1 Garand rifles and got killed as a result.
Not to be left with no recourse, the psychological aspect of training the troops were updated to include the preparation of troops in the act of killing enemy troops. And it worked, quite too well some might say.
In Vietnam, the troops now armed with higher capacity (30 rounds of 5.56mmx45 compared to the 8 rounds per clip of 30-06 on the Garand) fully automatic rifles (Colt M-16a1) and the mind set that we shall kill kill kill and make blood blood blood flow to make the grass grow grow grow let out tremendous salvos of fire on enemy troops, at least when their M-16s were not jamming.
The US armed forces again learned the hard way that this was not very effective, this so called "spraying and praying". Low hit ratios resulted of course in a low number of enemy kills.
As a result, the next incarnation of the M-16 rifle, the M-16a2 had an 0-1-3 trigger group, meaning the rifle could be put on safe, semiauto or three round burst mode of fire only. No more full auto.
From a tactical point of view, fully automatic fire is only good for suppressive fire or when one is outnumbered in a close quarter situation. If you ever have the chance, try and shoot a firearm in full auto, you will most likely get two or three hits on the target and the rest will be sprayed all over. If you are in the USA, contact Front Sight firearms training institute, they offer free submachinegun courses to qualified people. You don't have to be with LE, just have a clean record.
"The average rounds expended per kill with the M-16 in Vietnam was 50,000. Snipers averaged 1.3 rounds. The cost difference was $2,300 v. 27 cents."