This ammo pouch attachment was a bit frustrating, and I could not find any information online on how to attach the ammo pouch to the ammo hanger. I finally brought my gun to a gentleman who worked on M60s, and he showed me how to attach the ammo pouch to the M60.
This is a bit of information that I could not find online, and there is no guide, so I figured that I would write mini guide, with pics, on how to attach the ammo pouch.
If you're wondering why one should even use an ammo pouch, when shooting loose belts is so much cooler (think Rambo), it is because shooting loose belts can damage the gun. The gun is damaged by the potential whipping action of the belt.
It is important for a civilian M60 owner to use an ammo pouch and not shoot loose belts.
Here is a pic of an M60's top cover that is shot without an ammo carrier. The top cover is marred because shooting loose belts will cause the belt to whip upwards and dent or mar the top cover.
Anyone who owns or aspires to own a civilian M60 should read Thomas Hoel's Civilian M60 Owner's Guide:
http://www.machinegunpriceguide.com/html/m60_part_1.HTM
Certain practices in the military would not be wise in the civilian world, when it comes to your M60. If you are going to take away two things from Hoel's guide, it is these two things: 1. Do not shoot the M60 using the integral bipod; 2. Do not shoot loose belts, without an ammo carrier or pouch. The main reason for these two pieces of advice have to do with the fact that a military M60 is replaceable, whereas a civilian M60 is not, due to the Hughes prohibition, and over the generations of use, a civilian M60 that is shot from the bipod or without an ammo pouch will sustain irreplaceable or very expensive damage.