I have seen this a few times, and in my youth, I did it once myself. We had loaded a few thousand varmint rounds in 223, 222 and other, and a few primers spilled on the bench. Using my hand, I simply raked the primers into a primer tray for inserting into the Dillion primer tubes. Unknown to me at the time, there were a few SPP lying on the back of the bench, and they become mixed with the SRP.
Once we began our annual P-dog shoots, a couple of days into the shoot I opened the box of ammo that had the inadvertent pistol primers loaded. About every 3-4 rounds fired, I noticed gas blow back into my face (Thankfully, I was wearing shooting glasses), and I noticed the 222 load had an occasional pieced primer. I stopped shooting that box, and when I switched to another, the problem went away.
Upon returning home, I decapped the brass and measured and then discovered I had loaded a few with SPP instead. That taught me a valuable lesson.