The Lee 150 fngc that I have throws a .299 nose with 2% tin and 4% antimony. The drive bands throws just shy of .310. If I add more tin I can get it to a little over .310/.2995 give or take. It shoots very very good out of the levers and not so much out of the 340 and 840 bolt guns. Or you can order from Tom at Accurate Molds the 31-155J which is a very close design and spec it out with a .299 nose and .311 drive bands and problem solved. I have both and the Accurate will shoot out of all my 30 cals. My specs at Accurate is WW alloy but I cast with the 2/4 alloy and get .299/.3115. None of my levers will take a .300 nose either if I crimp in the crimp grove.
Hope the info is useful.
Tony