I just purchased a new lee collet neck die. I've never used these before, but have used other brands.

I resized some .243 win shells, and noticed that the neck was only being resized to .243" and the bullet was not seating firmly in the shell. I tore the die apart, and measured the mandrel. It was .240". This is the same diameter that my full length dieresizes brasstoo, and it firmly holds the bullet. So I don't think that the mandrel is the problem.

I am using a Rock Chucker Supreme press, and Winchester brass.

Am I not applying enough pressure? It sure seems like I am -- directionsstate that only25# is necessary. I can see where the collet is leaving rings in the outside of the brass. I am also running a nylon brush through the neck to remove excess powders, crud, etc before I resize. Am I perhaps doing something else wrong? I am turning the die one turns after makingthe dietouch the shell holder.Any ideas or suggestions would be appreciated. Thanks.