Tub Spout Removal

Hi all. I'm having trouble removing my tub spout. There does not appear to be a set screw holding in on, so I'm guessing it is a screw-on . I've tried to turn it counter-clockwise, but it is not budging. I'm afraid of applying to much pressure and ruining the copper pipe. Are there any tricks to remove it?

Thanks
-Stan

 

I usually bust the outer shell off the die cast spouts then get a wrench on the copper stub and unscrew the spout. No chance of breaking off the stub out is a good thing!