The Italeri kit is the best, and in some cases only , source for many
of those weapons. I've found that the side arms in that kit are the
best castings out there, particularly the Colt 1911. The Tamiya and DML
sidearm offerings are too detailed with out of scale details to make
sure they are visible, and the overall shapes just aren't right.You
might look into some of the DML kits, like the
IDF kits for the Uzi and Galil, though the Uzi that comes with the
Italeri kit is a good one.
DML has some kits with M14s also. There's Gulf War era US Sniper Team with
an M21 (sniper version of the M14), and then there's a Vietnam kit of the old mechanical mule that
has two grunt figures and one (maybe both, can't remember) has an M14.
DML also has the M16 and AK47 family kits, which provide every
concievable variant of both weapons and several accessories as well.
There's an HK family kit on top of that, with the whole HK assualt
weapon/SMG family, including MP5-PDWs in carrying cases.