DON'T DO THAT!!! If you check with any competent reloading authority they will tell you enlarging the flash holes is DANGEROUS. Uniforming the primer pocket does just that, makes the primer pocket uniform it does nothing to the flash hole. Uniforming a primer pocket is like blue printing an engine, make everything fit as it was designed. You can debur the the inside of the flash hole with the proper tool for more uniform ignition but on the average handgun cartridge this is not needed unless you're building super accurate target loads.

If you need more fire from the primer get a hotter primer don't mess with 25,000 to 60,000 psi.

Rant over, Pecos