Most electro markers are capable of firing "fully Auto", I was looking at an intimidator today that was capable of fully auto.
I have heard that fully auto paintball markers are not actually fully auto in the true sense.
Electronically assisted is not the same as fully auto.
I don't think that even in the USA you are allowed fully automatic weapons (you can't keep one at home under your bed) but "Fully Auto " paintball markers seem to be ok.
I would suggest that you call Diablo Direct who are the importers of the e-rex range of markers and ask them directly rather than relying on bull**** from rival companies.
I am sure that with Diablo's experience and time in paintball, they would not try and supply an illegal marker, they are the biggest paintball company in the world after all.
Campaign, one of the UK's biggest and most respected sites is selling them, Fat Bob's is selling them, Diablo is selling them. Sound like there are some big hitters behind these e-rex's.
Diablo's number is 01273 696700
Rob