I mentioned my on again off again ignition problems To Ed Hubel the other day (By email)
He had several sugguestions but the very first one was to make sure I roll crimped to 2.65 inches or shorter (With 3" shells).
I'll be honest, I haven't been paying attention to the LOA.
I just measured a few that I had trouble with and guess what. 2.796".
The lack of compression may well be the source of my erratic shells.