I shoot it all the time, but I have a stock of it from match shooting with the army and I know that it wasn't abused or fired full auto. As Jimro notes above, case prep is key to getting it to shoot well and the M118 is well worth getting. The M 852 match round does not have a crimped in primer and is as good as it gets for GI ammo. I use it in all my 308 rifles.
Most 7.62 NATO GI brass has been fired through a machine gun. They can be pretty hard on 'em. The M-60 would stretch the web area pretty badly and drastically shortened the life of the cases fired through them. I've never bothered trying the brass from our current M-240, but I suspect it might have the same issues.
The life cycle of GI brass sold in the US is generally something like this:
Fired by the troops on bases in the US.
It is then policed up and turned in to the Ammo Supply Point salvage yard where it is weighed (weight must match predicted weight by number of rounds issued) and checked for live rounds on large screens.
Collected en masse and turned over to DOL and when sufficient tonnage is on hand, it somehow gets sold to bidders.
Sold by the bidder to jobbers or direct to the customer.
9mm, 45 ACP and 38 Special (not seen much anymore) don't have the issues that the ammo fired through the MGs have and are a safe bet to buy.
US Army Distinguished Rifleman
Washington State Distinguished Rifleman
NRA Police Distinguished Expert