Sounds like a primer seating issue. I've reloaded thousands of rounds on a 650. I recently started loading again after a layoff of almost two years and had a few rounds with primers that were not seated deep enough and did not go bang. The feel of a properly seated primer is something that comes with experience. Although you are using carbide dies try lightly lubing your cases. I use the Dillon lube in a pump sprayer. I put my cases in a copy paper box top, get all laying on their side, and give them a few shots of lube. Shake the box to distribute the lube and let it dry for a few minutes before you load. Makes the press run smoothly so you are better able to feel what is happening.