You can turn a pilot to about 0.001" fat, which would equal the actual bore dimension, easily, then use emery cloth to take it down to a pilot dimension. That gives it a smooth surface, like it would have had if it been ground.
One can actually take the pilot blank out of the lathe, and keep trying it for fit, in the bore, once you start with the emery, and get the closest fit possible that way. You want it to just slide in, and be able to turn. If you have a long enough bed on the lathe, pull the tailstock back, and use the rifle barrel as a gauge, without taking the blank out of the chuck.