Just don't run the chamber reamer in the die blank all the way.
Main thing is get some cases that fit, then do everything else with a generic neck sizer. Once the case fits no need to ever Full Length size again
To your point on worrying them down. My 25 Krag working from a bag of 50 new WW 30/40 cases ended up with 40 that are good fits extract well and only need a light neck sizing after firing. Some lost getting the neck wall thickness down right, needed a fair amount of neck turning to chamber. Forming ran them through 7mm08, 260 Remington then .25/08 form trim dies all from CG4D's stock dies. When I skipped the 260 Rem step lost a few to collapsed necks
Same rifle same methods some old 30 Army head stamped brass would not chamber. Hanging up at the cases web. They had to be turned down just a bit on the lathe. No amount of sizing would reduce the brass in front of the rim.
Neck size is with one of CH4D's interchangeable bushing neck size dies using a home made insert. Turned it on the lathe drilled reamed and lapped it out to suit the chamber wall thickness and bullet.
Boats
