Kerrdog,
You wrote:
I only did so because the bullets were loose after FL sizing. The second batch I neck sized AFTER full length sizing, and that tightened them up. No crimping involved.


What do you mean "the bullets were loose?" Were they flopping around? Falling into the case? This statement worried me some as I have never had that happen to me. Could it be your expander ball is bigger than it should be?

Is sounds like the folks here have given some excellent advise. Although I might add that extra kick could be you experiencing excess pressures due to your crimp.

Just my two cents worth!!! Be safe!!!!!