I would bet that a large percentage of them would fire just fine. But, the prospect of one not functioning properly and getting a bullet stuck in the bore scares me enough to toss them. Rifle and pistol primers are relatively cheap. I just prefer to use new ones.
I will reuse shotshell primers, though, which I have removed from cases. But, the pellet has some protection from pressure of the decapping pin by the way the shotshell primer is made.
