Brownells has a kit that will work.  You hack off the barrel a little longer then you want and then there is a piloted crown cutter that you put in a drill.  NRA rifleman showed doing this to a 22lr in there magazine last month (think it was last month).  Of just find someone with a metal lathe.  I did an AR-15 barrel for my dad on a lathe at a place I use to work, I still am pretty good friends with the manager and they have a full machine shop in the buisness.