Seems the general consensus is that Federal primers in the Lee Pro 1000 are the culprit and should be avoided because they are softer than others and "potentially" more likely to detonate.
Here are a couple forum threads on this from elsewhere. Several mishaps are reported, both happened with Federal primers. Quite a few have posted that they use Federal in the Lee with no problems. IMHO, WW primers would also be just fine, it's really only Federal that I know to be softer.
The best solution posted seems to be to get a Dillon progressive press
Hope this helps, I would say you have to make your own decision on this based on what you read there.