Size of expander plugs

[brian_a_mcmillen]

I am wondering about what diameter size below the diameter size of a given projectile should the expander plug be and is there a difference between cast bullets and jacketed bullets.  Like for a .452 lead bullet….should the expander plug be .451, .450 etc.  I think I need to expand my cases more to keep from resizing my lead projectiles by forcing them into a case that’s too narrow.

Ideas??

[CDRT]

I use the same expander plug for both lead and jacketed bullets.  Never had a problem.  It's the one that came with the press, never measured it.