I have the Lee 150f boolit, sizing to 309 and using IMR 4227 powder. I started with the Lyman book starting load of 16.4 and have worked up to 19gn now in 1/2gn lots.
My 19gn loads are running faster (over my chrony) than Lyman shows for the 21gn max loads. Cases show no pressure signs.
Should I be worried about over Pressure?
Do I need a 150gn hunting boolit going that fast?