I have abroad full auto blank guns and am considering alternate Flash, Pepper rounds in 9 mm. Would it be better on full auto or semi auto with high dose pepper or CS gas rounds. I use them in France not England.
Not really. Most "rubber bullets" don't really do much to stop people but can sometimes be painful. Pain may or may not convince an attacker to go away. LEO in the U.S. don't use them much any longer, mostly because of the dual prongs of limited success and claims of police brutality.
I'd stick with regular pepper spray, quite honestly.