I'd say 90-95% of my .308 is range pickup. I make sure I go to the range 1-3 times a week just before and during hunting season as most people sighting in for their hunt don't pickup brass or reload. Got loads of .308, .30-06, .30-30, 7mm RM, and .303B this way.
After about 2 years of regular range collection I'm sitting on around 1000 .308 cases. I sort them by brand and sometimes weight sort as well but haven't noticed any difference in doing so.
There are at least a few other range rats collecting brass at the same range so my guess is I've collected maybe 10-20% of it in that time.
Several manufactures have put a hold on retail sales due to military demand from what I understand from a few of the site sponsors.
Several manufacturers have published announcements denying this. They admit to temporarily halting production of some less popular cartridges but that mil/LE purchasing has had nothing to do with the shortages. It's simply a matter of demand far outstretching supply as many thousands of people got into reloading at the same time after the Sandy Hook shooting and the panic buying and hoarding hasn't stopped since.
Only a couple of the manufacturers even offer NATO spec brass (much tighter hardness tolerances on the cases at various points) so those that don't have no reason to stop supplying civilians when they don't have significant military sales.
Could they be lying? Possibly, but I don't think so personally. When trust in your name is such a huge part of this industry it would be corporate suicide to lie to your customers (unless it's an Obama conspiracy like some theorize but that's another matter).