1.506 will pop out of the tube and jam under the lifter, 1.544 and 1.652 seem to be working without doing that BUT they are jamming every handful of rounds going into the chamber. They catch on the rim of the brass even though they go through a Lee Factory Crimp die. Thank you for any info. I am kind of frustrated with the gun right now. I am tempted to polish the chamber opening, and widen out the loading opening at this point, but would still be stuck with the under lifter jams.