Primers
Its been generally accepted that when primers loosen or fall out that the load is too HOT, obviously a blown or pierced cup is an immediate indication of problems, but the loose cup doesnt manifest itself until it hits the loading bench. So, if you didnt fire the factory rounds to aquire the cases, then you have no accurate info on the case history.
What priming tool are you using, as the feel from different kinds can be decieving, there should be a subtle resistance/pressure when it goes in and a definite stop when it seats. If I feel that the seating pressure is odd, I'll test the un-sized cases in the lot that I'm working on with a hand held decap rod to see if the primer will come out easily, if so , it probably wont hold a new cup.
Is there a risk and whats a worst case , Its your face and your digits, so I guess its your decision..... I have pulled down a bunch of ammo because It was suspect, but I have also had an HK SL-7 grenade in my face from the CBC 75, 7.62 surplus ammo that came on the market years ago. I was lucky, but others werent.
As to the modified FN ammo thats being sold, any ammo that destroys the case integrity on the first shot , I want nothing to do with!!
You can roll some very good ammo without getting into the danger zone that some folks think is neccessary to poke holes in paper. Load for accuracy and reliable function and your brass and weapon will last much longer. Sorry, didnt mean to ramble but you hit a trigger word. Hope this is useful to you.