M-16 vs. M-4
Never having been in combat I hesitate to add my 2 cents but it seems like standardizing on one weapon has been an obsession of the Army ever since WWII, according to articles I've read.
WWII infantry weapons: Garand, BAR, carbine, tommy gun, grease gun plus 1911s and various revolvers.
Next the do-everything M-14 to replace the rifle, BAR, carbine and submachine guns so I have read.
Now it's the M-4 basically and the M9 pistol. Seems like you can carry this one-size fits all idea too far - and that's why they had to bring back the M-14.
Again, I defer absolutely to those who have used these various weapons in combat and know a heckuva lot more than I ever will.
I'd be interested in hearing what forum members who are combat veterans think about the weapons they have used.