Arduino and HC-05 hardware serial issues
A simple 10k/20k voltage divider is enough to bring the 5V arduino logic-level voltage down to ~3.3 for the HC-05.  It worked for me anyway.

The default baud rate for HC-05 is 9600 baud.  So unless you've changed this with AT- commands you will run into issues.  Although I read that some boards default to 38400 - best check your documentation.  All the cheap HC-05 boards I've tested default to 9600.