#2 Center drill in the end will give expansion close to factory SD ammo. For a legal aspect I wouldnt use it for SD. Try a couple and fire them into water or wet newspaper. If you dont have a lathe clamp a block of wood in drill press and drill a 13/32 hole about 3/16 dp then change the bit to the #2 CD. Should give yo pretty good concentricity.
Concentrated power is not rendered harmless by the good intentions of those who create it.