The Hornady bullets should be fine. The size of the front end of your chambers is probably more critical than the exit bores.

If you want to use the Hornadys, just use the normal precautions you would always use in working up a new load in any cartridge and gun that is new to you - viz., select a starting load from appropriate published data and work up incrementally. It would seem highly unlikely the Hornadys at .430" would cause any trouble.