Use two rods with the balls you have.  Start it in, use one rod as a stop against something solid, use the other rod for smacking the ball so that it expands out into the rifling.  Push it back out the end you went in.  I use some store bought brass and/or steel rods, not a cleaning rod.  If you're planning on shooting cast, size them .311 if the neck will permit it.  Some modern brass I have will allow me .311, some older stuff, REM-UMC 30USA will only allow me .310.  Slug both ends of your barrel, sometimes you run into a reverse taper with the groove diameter getting bigger as you go toward the muzzle.