There are many, many dealers in brass. Right now the supply of military surplus is limited. They are using it over seas... Shotgunnews.com has suppliers of reloading components. If you are talking 1,000 quantity, they might be a good place to visit. gibrass.com, patsreloading.com, Hi-tecammo.com, cheyennebrass.com, often have once fired surplus. River Valley has a good rep. I remember when it was Dexter Automotive... Wideners, in times of peace, has once fired and new military. IMI (Israeli Military Industries). They did have a south American brand... short supply now. Google it and no telling what will turn up.
As said, the military "crimps" primers to keep them from coming out and jamming actions especially in full auto fire. Guns tend to warm up full auto. Military Match cases usually are not crimped. Otherwise... The Japanese used a "stake" crimp, 3 points around the circle. You can remove it with a pocket knife. The first I did, an '06 I got carried away and it would no longer hold a primer... dropped right out... One quick turn. Enough. Case Mouth chamfer tools work o.k. I have used a LEE until my fingers got sore. RCBS and others make a crimper that swages the brass back and puts a nice rounded edge on the hole. I think I like the CH best. It works above the press, easier to see. I would lube the punch with case lube every few. One method, much recommended long ago with lots of surplus '06 around, there are counter sinks for flat headed screws... you chuck one of them in a drill and just touch the hold to the sink and it cuts that nice tapered edge while cutting away the crimp... I don't recall the tool numbers... luck, happy trails.